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Chen S, Wu T, Chen H, Zhou W, Gao Y, Yao N, Jiang L, Huang Z. Broadband Room-Temperature Photodetection via InBiTe 3 Nanosheet. Small 2024:e2312219. [PMID: 38639342 DOI: 10.1002/smll.202312219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/05/2024] [Indexed: 04/20/2024]
Abstract
Broadband room-temperature photodetection has become a pressing need as application requirements for communication, imaging, spectroscopy, and sensing have evolved. Topological insulators (TIs) have narrow bandgap structures with a wide absorption spectral response range, which should meet the requirements of broadband detection. However, owing to their high carrier concentration and low carrier mobility resulting in poor noise equivalent power (NEP), they are generally considered unsuitable for photodetection. Here, InBiTe3 alloy nanosheet formed by doping In2Te3 into Bi2Te3(≈ 1:1) is utilized, effectively improving carrier mobility by over ten times while maintaining a narrow bandgap structure, to fabricate a broadband photodetector covering a wide response range from visible to millimeter wave (MMW). Under the synergistic multi-mechanism of the photoelectric effect in the visible-infrared region and the electromagnetic-induced potential well (EIW) effect in Terahertz band, the performance of NEP = 75 pW Hz-1/2 and response time τ ≈100 µs in visible to infrared band and the performance of NEP = 6.7 × 10-3 pW Hz-1/2, τ ≈8 µs in Terahertz region are achieved. The results demonstrate the promising prospects of topological insulator alloy (like InBiTe3) nanosheet in optoelectronic detection applications and provide a direction for the research into high-performance broadband photoelectric detectors via TIs.
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Affiliation(s)
- Shijie Chen
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-Lane Xiangshan, Hangzhou, 310024, P. R. China
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
- University of Chinese Academy of Sciences, 19 Yu Quan Road, Beijing, 100049, P. R. China
| | - Tuntan Wu
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-Lane Xiangshan, Hangzhou, 310024, P. R. China
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
- University of Chinese Academy of Sciences, 19 Yu Quan Road, Beijing, 100049, P. R. China
| | - Hang Chen
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-Lane Xiangshan, Hangzhou, 310024, P. R. China
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
- University of Chinese Academy of Sciences, 19 Yu Quan Road, Beijing, 100049, P. R. China
| | - Wei Zhou
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
| | - Yanqing Gao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
| | - Niangjuan Yao
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
| | - Lin Jiang
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
| | - Zhiming Huang
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-Lane Xiangshan, Hangzhou, 310024, P. R. China
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai, 200083, P. R. China
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2
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Huang S, Ghosh N, Niu C, Chen YP, Ye PD, Xu X. Optically Gated Electrostatic Field-Effect Thermal Transistor. Nano Lett 2024. [PMID: 38639471 DOI: 10.1021/acs.nanolett.3c05085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Dynamic tuning of thermal transport in solids is scientifically intriguing with wide applications for thermal transport control in electronic devices. In this work, we demonstrate a thermal transistor, a device in which heat flow can be regulated using external control, realized in a topological insulator (TI) through the topological surface states. The tuning of thermal transport is achieved by using optical gating of a thin dielectric layer deposited on the TI film. The gate-dependent thermal conductivity is measured using micro-Raman thermometry. The transistor has a large ON/OFF ratio of 2.8 at room temperature and can be continuously and repetitively switched in tens of seconds by optical gating and potentially much faster by electrical gating. Such thermal transistors with a large ON/OFF ratio and fast switching times offer the possibilities of smart thermal devices for active thermal management and control in future electronic systems.
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Affiliation(s)
- Shouyuan Huang
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Neil Ghosh
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Chang Niu
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yong P Chen
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, United States
| | - Peide D Ye
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, United States
| | - Xianfan Xu
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
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3
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Li YW, Chen MN, Dai JY, Zhou Y. Guiding infrared electromagnetic waves through TI nanowires with extremely large wavenumber and azimuthal index. J Phys Condens Matter 2024; 36:275001. [PMID: 38537285 DOI: 10.1088/1361-648x/ad3876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024]
Abstract
In this paper, the dispersion relations of the surface plasmon polaritons (SPPs) in TI nanowires have been investigated. For simplicity, TI nanowire has been modeled as a dielectric cylinder with a conductive surface, the conductivity of which is an anti-symmetric tensor. The off-diagonal terms of the conductivity tensor only slightly change the dispersion relations. Due to small conductivities, these SPPs have extremely large wavenumbers and azimuthal indices; the electric fields are tightly confined near the conductive surface. For high-order modes, cut-off phenomena have been observed. In the end, the effects of losses and much larger bulk permittivities on the dispersion relations of surface plasmons have been discussed. The simple model proposed in this paper can be directly applied to other materials with arbitrary surface conductivity. Our investigations show that TI nanostructures are promising platforms for nanophotonic applications in the future.
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Affiliation(s)
- Y W Li
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - M N Chen
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - J Y Dai
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - Yu Zhou
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
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4
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Choi GS, Park S, An ES, Bae J, Shin I, Kang BT, Won CJ, Cheong SW, Lee HW, Lee GH, Cho WJ, Kim JS. Highly Efficient Room-Temperature Spin-Orbit-Torque Switching in a Van der Waals Heterostructure of Topological Insulator and Ferromagnet. Adv Sci (Weinh) 2024:e2400893. [PMID: 38520060 DOI: 10.1002/advs.202400893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 03/25/2024]
Abstract
All-Van der Waals (vdW)-material-based heterostructures with atomically sharp interfaces offer a versatile platform for high-performing spintronic functionalities at room temperature. One of the key components is vdW topological insulators (TIs), which can produce a strong spin-orbit-torque (SOT) through the spin-momentum locking of their topological surface state (TSS). However, the relatively low conductance of the TSS introduces a current leakage problem through the bulk states of the TI or the adjacent ferromagnetic metal layers, reducing the interfacial charge-to-spin conversion efficiency (qICS). Here, a vdW heterostructure is used consisting of atomically-thin layers of a bulk-insulating TI Sn-doped Bi1.1Sb0.9Te2S1 and a room-temperature ferromagnet Fe3GaTe2, to enhance the relative current ratio on the TSS up to ≈20%. The resulting qICS reaches ≈1.65 nm-1 and the critical current density Jc ≈0.9 × 106 Acm-2 at 300 K, surpassing the performance of TI-based and heavy-metal-based SOT devices. These findings demonstrate that an all-vdW heterostructure with thickness optimization offers a promising platform for efficient current-controlled magnetization switching at room temperature.
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Affiliation(s)
- Gyu Seung Choi
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Sungyu Park
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Eun-Su An
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Juhong Bae
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Inseob Shin
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Beom Tak Kang
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Choong Jae Won
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
| | - Sang-Wook Cheong
- Center for Complex Phase of Materials, Max Planck POSTECH/Korea Research Initiative, Pohang, 37673, Republic of Korea
- Laboratory for Pohang Emergent Materials, Department of Physics, POSTECH, Pohang, 37673, Republic of Korea
- Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, NJ, 08854, USA
| | - Hyun-Woo Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Gil-Ho Lee
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Won Joon Cho
- Device Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd, 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do, 16678, Republic of Korea
| | - Jun Sung Kim
- Department of Physics, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
- Center for Artificial Low Dimensional Electronic Systems, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
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5
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Hong S, Kim D, Kim J, Park J, Rho S, Huh J, Lee Y, Jeong K, Cho M. Enhanced Photocharacteristics by Fermi Level Modulating in Sb 2 Te 3 /Bi 2 Se 3 Topological Insulator p-n Junction. Adv Sci (Weinh) 2024; 11:e2307509. [PMID: 38161227 PMCID: PMC10953576 DOI: 10.1002/advs.202307509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/13/2023] [Indexed: 01/03/2024]
Abstract
Topological insulators have recently received attention in optoelectronic devices because of their high mobility and broadband absorption resulting from their topological surface states. In particular, theoretical and experimental studies have emerged that can improve the spin generation efficiency in a topological insulator-based p-n junction structure called a TPNJ, drawing attention in optospintronics. Recently, research on implementing the TPNJ structure is conducted; however, studies on the device characteristics of the TPNJ structure are still insufficient. In this study, the TPNJ structure is effectively implemented without intermixing by controlling the annealing temperature, and the photocharacteristics appearing in the TPNJ structure are investigated using a cross-pattern that can compare the characteristics in a single device. Enhanced photo characteristics are observed for the TPNJ structure. An optical pump Terahertz probe and a physical property measurement system are used to confirm the cause of improved photoresponsivity. Consequently, the photocharacteristics are improved owing to the change in the absorption mechanism and surface transport channel caused by the Fermi level shift in the TPNJ structure.
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Affiliation(s)
- Seok‐Bo Hong
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Dajung Kim
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Jonghoon Kim
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Jaehan Park
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Seungwon Rho
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Jaeseok Huh
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Youngmin Lee
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
| | - Kwangsik Jeong
- Division of Physics and Semiconductor ScienceDongguk UniversitySeoul04620Republic of Korea
| | - Mann‐Ho Cho
- Department of PhysicsYonsei University50 Yonsei‐roSeoul03722Republic of Korea
- Department of System Semiconductor EngineeringYonsei University50 Yonsei‐roSeoul03722Republic of Korea
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6
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Shang C, Liu S, Jiang C, Shao R, Zang X, Lee CH, Thomale R, Manchon A, Cui TJ, Schwingenschlögl U. Observation of a Higher-Order End Topological Insulator in a Real Projective Lattice. Adv Sci (Weinh) 2024; 11:e2303222. [PMID: 38214384 PMCID: PMC10953588 DOI: 10.1002/advs.202303222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 08/15/2023] [Indexed: 01/13/2024]
Abstract
The modern theory of quantized polarization has recently extended from 1D dipole moment to multipole moment, leading to the development from conventional topological insulators (TIs) to higher-order TIs, i.e., from the bulk polarization as primary topological index, to the fractional corner charge as secondary topological index. The authors here extend this development by theoretically discovering a higher-order end TI (HOETI) in a real projective lattice and experimentally verifying the prediction using topolectric circuits. A HOETI realizes a dipole-symmetry-protected phase in a higher-dimensional space (conventionally in one dimension), which manifests as 0D topologically protected end states and a fractional end charge. The discovered bulk-end correspondence reveals that the fractional end charge, which is proportional to the bulk topological invariant, can serve as a generic bulk probe of higher-order topology. The authors identify the HOETI experimentally by the presence of localized end states and a fractional end charge. The results demonstrate the existence of fractional charges in non-Euclidean manifolds and open new avenues for understanding the interplay between topological obstructions in real and momentum space.
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Affiliation(s)
- Ce Shang
- King Abdullah University of Science and Technology (KAUST)Physical Science and Engineering Division (PSE)Thuwal23955‐6900Saudi Arabia
| | - Shuo Liu
- State Key Laboratory of Millimeter WavesSoutheast UniversityNanjing210096China
| | - Caigui Jiang
- Institute of Artificial Intelligence and RoboticsXi'an Jiaotong UniversityXi'an710049China
| | - Ruiwen Shao
- State Key Laboratory of Millimeter WavesSoutheast UniversityNanjing210096China
| | - Xiaoning Zang
- King Abdullah University of Science and Technology (KAUST)Physical Science and Engineering Division (PSE)Thuwal23955‐6900Saudi Arabia
| | - Ching Hua Lee
- Department of PhysicsNational University of SingaporeSingapore117551Republic of Singapore
- Joint School of National University of Singapore and Tianjin UniversityInternational Campus of Tianjin UniversityFuzhou350207China
| | - Ronny Thomale
- Institut für Theoretische Physik und AstrophysikUniversität Würzburg97074WürzburgGermany
| | | | - Tie Jun Cui
- State Key Laboratory of Millimeter WavesSoutheast UniversityNanjing210096China
| | - Udo Schwingenschlögl
- King Abdullah University of Science and Technology (KAUST)Physical Science and Engineering Division (PSE)Thuwal23955‐6900Saudi Arabia
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7
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Li W, Wang CM. An ideal candidate for observing anomalous Hall effect induced by the in-plane magnetic field. J Phys Condens Matter 2024; 36:205001. [PMID: 38335548 DOI: 10.1088/1361-648x/ad2804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 02/09/2024] [Indexed: 02/12/2024]
Abstract
The anomalous Hall effect induced by the in-plane magnetic field (anomalous planar Hall effect) has recently attracted a lot of interests due to its numerous advantages. Although several schemes have been put forward in theory, experimental observations in many materials so far are often accompanied by planar Hall effects due to other mechanisms, rather than the pure anomalous planar Hall effect (APHE). We propose the surface state of the strained topological insulator as an ideal candidate to observe this effect. The surface state exhibits a pure APHE, characterized by a linear dependence on the magnetic field and a 2πperiodicity, which remains robust against the scattering of non-magnetic and various magnetic impurities, as long as the uniaxial strain preserves mirror symmetry. Although a general strain that breaks the mirror symmetry can induce the conventional Drude Hall effect, the anomalous contribution remains dominant. Furthermore, we present a feasible scheme to distinguish between the two contributions based on their distinct magnetic field dependencies. Our work is of great significance for promoting experimental observation of the APHE and provides reference value in the search for other realistic materials.
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Affiliation(s)
- Wenrong Li
- Department of Physics, Shanghai Normal University, Shanghai 200234, People's Republic of China
| | - C M Wang
- Department of Physics, Shanghai Normal University, Shanghai 200234, People's Republic of China
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8
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Jiang YC, Kariyado T, Hu X. Topological electronic states in holey graphyne. Nanotechnology 2024; 35:195201. [PMID: 38295413 DOI: 10.1088/1361-6528/ad2483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 01/31/2024] [Indexed: 02/02/2024]
Abstract
We unveil that the holey graphyne (HGY), a two-dimensional carbon allotrope where benzene rings are connected by two -C≡C- bonds fabricated recently in a bottom-up way, exhibits topological electronic states. Using first-principles calculations and Wannier tight-binding modeling, we discover a higher-order topological invariant associated withC2symmetry of the material, and show that the resultant corner modes appear in nanoflakes matching to the structure of precursor reported previously, which are ready for direct experimental observations. In addition, we find that a band inversion between emergentg-like andh-like orbitals gives rise to a nontrivial topology characterized byZ2invariant protected by an energy gap as large as 0.52 eV, manifesting helical edge states mimicking those in the prominent quantum spin Hall effect, which can be accessed experimentally after hydrogenation in HGY. We hope these findings trigger interests towards exploring the topological electronic states in HGY and related future electronics applications.
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Affiliation(s)
- Yong-Cheng Jiang
- Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba 305-8571, Japan
| | - Toshikaze Kariyado
- Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
| | - Xiao Hu
- Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
- Graduate School of Science and Technology, University of Tsukuba, Tsukuba 305-8571, Japan
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9
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Noureen S, Rehman SU, Batool SM, Ali J, Zhang Q, Batool SS, Wang Y, Li C. Tailoring Bi 2Se 3 Topological Insulator for Visible-NIR Photodetectors with Schottky Contacts Using Liquid Phase Exfoliation. ACS Appl Mater Interfaces 2024; 16:8158-8168. [PMID: 38301155 DOI: 10.1021/acsami.3c15315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Layered semiconductors of the V-VI group have attracted considerable attention in optoelectronic applications owing to their atomically thin structures. They offer thickness-dependent optical and electronic properties, promising ultrafast response time, and high sensitivity. Compared to the bulk, 2D bismuth selenide (Bi2Se3) is recently considered a highly promising material. In this study, 2D nanosheets are synthesized by prolonged sonication in two different solvents, such as N-methyl-2-pyrrolidone (NMP) and chitosan-acetic acid solution (CS-HAc), using the liquid-phase exfoliation (LPE) method. X-ray diffraction confirms the amorphous nature of exfoliated 2D nanosheets with maximum peak intensity at the same position (015) crystal plane as that obtained in its bulk counterpart. SEM confirms the thin 2D nanosheet-like morphology. Successful exfoliation of Bi2Se3 nanosheets up to five layers is achieved using CS-HAc solvent. The as-synthesized 2D nanosheets in different solvents are employed to fabricate the photodetector. At minimum selected power density, the photodetector fabricated using exfoliated ultrathin 2D nanosheets exhibits the highest range of responsivity, varying from 15 to 2.5 mA/W, and detectivity ranging from 2.83 × 109 to 6.37 × 107. Ultrathin 2D Bi2Se3 nanosheets have fast rise and fall times, ranging from 0.01 to 0.12 and 0.01 to 0.06 s, respectively, at different wavelengths. Ultrathin Bi2Se3 nanosheets have improved photodetection parameters as compared to multilayered nanosheets due to the high surface to volume ratio, reduced recombination and trapping of charge carrier, improved carrier confinement, and faster carrier transport due to the thin layer.
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Affiliation(s)
- Sadaf Noureen
- School of Science, Minzu University of China, Beijing 100081, China
- Optoelectronic Research Laboratory (OERL), Department of Physics, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad 45550, Pakistan
| | - Sajid Ur Rehman
- School of Science, Minzu University of China, Beijing 100081, China
| | - Syeda Maria Batool
- Electric Material and Nanotechnology Lab, North Dakota State University, Fargo, North Dakota 58102, United States
| | - Junaid Ali
- Optoelectronic Research Laboratory (OERL), Department of Physics, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad 45550, Pakistan
| | - Qifeng Zhang
- Electric Material and Nanotechnology Lab, North Dakota State University, Fargo, North Dakota 58102, United States
| | - Syeda Sitwat Batool
- School of Science, Minzu University of China, Beijing 100081, China
- Optoelectronic Research Laboratory (OERL), Department of Physics, COMSATS University Islamabad, Park Road, Chak Shahzad, Islamabad 45550, Pakistan
| | - Yang Wang
- School of Science, Minzu University of China, Beijing 100081, China
- Optoelectronics Research Center, Minzu University of China, Beijing 100081, China
| | - Chuanbo Li
- School of Science, Minzu University of China, Beijing 100081, China
- Optoelectronics Research Center, Minzu University of China, Beijing 100081, China
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10
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Wen L, Zhang Q, Shi J, Wang F, Wang S, Chen Z, Yue Y, Gao Y. Layered Topological Insulator MnBi 2Te 4 as a Cathode for a High Rate Performance Aqueous Zinc-Ion Battery. ACS Nano 2024. [PMID: 38335299 DOI: 10.1021/acsnano.4c01137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
Recently, the topological insulator MnBi2Te4 has aroused great attention owing to its exotic quantum phenomena and intriguing device applications, but the superior performances of MnBi2Te4 have not been researched in the field of electrochemistry. By theoretical calculations, it is found that MnBi2Te4 exhibits excellent Zn2+ storage and transport properties. Therefore, it is speculated that MnBi2Te4 has excellent electrochemical performance in zinc-ion batteries (ZIBs). In this research, MnBi2Te4 as a pioneer has been explored in ZIBs, showing surprising electrochemical properties. The MnBi2Te4 electrode displays a high average discharge specific capacity (264.8 mA h g-1 at 0.40 A g-1), a competitive cycle life (88.6% of initial capacity after 400 cycles at 4.00 A g-1), and an excellent rate performance (average capacity retention rate of 95.1% from 0.40 to 8.00 A g-1) owing to the fast ion transport of the conductive topological surface state and dissipationless channel of the edge state. Surprisingly, the quasi-solid-state (QSS) MnBi2Te4/Zn battery delivers excellent Zn2+ storage capability and possesses a capacity retention of 79.9% after 1000 cycles at 4.00 A g-1. In addition, the QSS MnBi2Te4/Zn battery can exhibit excellent performance and the GCD curves maintain stability without distortion deformation even at temperatures of 0 and 75 °C.
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Affiliation(s)
- Li Wen
- Center for Nanoscale Characterization & Devices (CNCD), School of Physics and Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Qixiang Zhang
- Center for Nanoscale Characterization & Devices (CNCD), School of Physics and Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Junjie Shi
- Center for Nanoscale Characterization & Devices (CNCD), School of Physics and Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074, China
| | - Fei Wang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Industry-Education-Research Institute of Advanced Materials and Technology for Integrated Circuits, Anhui University, Hefei 230601, China
| | - Siliang Wang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Industry-Education-Research Institute of Advanced Materials and Technology for Integrated Circuits, Anhui University, Hefei 230601, China
| | - Zhiwei Chen
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Industry-Education-Research Institute of Advanced Materials and Technology for Integrated Circuits, Anhui University, Hefei 230601, China
| | - Yang Yue
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Yihua Gao
- Center for Nanoscale Characterization & Devices (CNCD), School of Physics and Wuhan National Laboratory for Optoelectronics (WNLO), Huazhong University of Science and Technology (HUST), Wuhan 430074, China
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11
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Zhong J, Yang M, Wang J, Li Y, Liu C, Mu D, Liu Y, Cheng N, Shi Z, Yang L, Zhuang J, Du Y, Hao W. Observation of Anomalous Planar Hall Effect Induced by One-Dimensional Weak Antilocalization. ACS Nano 2024; 18:4343-4351. [PMID: 38277336 DOI: 10.1021/acsnano.3c10120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
The confinement of electrons in one-dimensional (1D) space highlights the prominence of the role of electron interactions or correlations, leading to a variety of fascinating physical phenomena. The quasi-1D electron states can exhibit a unique spin texture under spin-orbit interaction (SOI) and thus could generate a robust spin current by forbidden electron backscattering. Direct detection of such 1D spin or SOI information, however, is challenging due to complicated techniques. Here, we identify an anomalous planar Hall effect (APHE) in the magnetotransport of quasi-1D van der Waals (vdW) topological materials as exemplified by Bi4Br4, which arises from the quantum interference correction of 1D weak antilocalization (WAL) to the ordinary planar Hall effect and demonstrates a deviation from the usual sine and cosine curves. The occurrence of 1D WAL is correlated to the line-shape Fermi surface and persistent spin texture of (100) topological surface states of Bi4Br4, as revealed by both our angle-resolved photoemission spectroscopy and first-principles calculations. By generalizing the observation of APHE to other non-vdW bulk materials, this work provides a possible characteristic of magnetotransport for identifying the spin/SOI information and quantum interference behavior of 1D states in 3D topological material.
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Affiliation(s)
- Jingyuan Zhong
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Ming Yang
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Jianfeng Wang
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Yaqi Li
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Chen Liu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Dan Mu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yundan Liu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Ningyan Cheng
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Zhixiang Shi
- School of Physics and Key Laboratory of the Ministry of Education, Southeast University, Nanjing 211189, People's Republic of China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Jincheng Zhuang
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China
| | - Yi Du
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China
| | - Weichang Hao
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China
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12
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Harrison K, Jeff DA, DeStefano JM, Peek O, Kushima A, Chu JH, Gutiérrez HR, Khondaker SI. In-Plane Anisotropy in the Layered Topological Insulator Ta 2Ni 3Te 5 Investigated via TEM and Polarized Raman Spectroscopy. ACS Nano 2024. [PMID: 38306703 DOI: 10.1021/acsnano.3c09527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
Layered Ta2M3Te5 (M = Pd, Ni) has emerged as a platform to study 2D topological insulators, which have exotic properties such as spin-momentum locking and the presence of Dirac fermions for use in conventional and quantum-based electronics. In particular, Ta2Ni3Te5 has been shown to have superconductivity under pressure and is predicted to have second-order topology. Despite being an interesting material with fascinating physics, the detailed crystalline and phononic properties of this material are still unknown. In this study, we use transmission electron microscopy (TEM) and polarized Raman spectroscopy (PRS) to reveal the anisotropic properties of exfoliated few-layer Ta2Ni3Te5. An electron diffraction and TEM study reveals structural anisotropy in the material, with a preferential crystal orientation along the [010] direction. Through Raman spectroscopy, we discovered 15 vibrational modes, 3 of which are ultralow-frequency modes, which show anisotropic response with sample orientation varying with the polarization of the incident beam. Using angle-resolved PRS, we assigned the vibrational symmetries of 11 modes to Ag and two modes to B3g. We also found that linear dichroism plays a role in understanding the Raman signature of this material, which requires the use of complex elements in the Raman tensors. The anisotropy of the Raman scattering also depends on the excitation energies. Our observations reveal the anisotropic nature of Ta2Ni3Te5, establish a quick and nondestructive Raman fingerprint for determining sample orientation, and represent a significant advance in the fundamental understanding of the two-dimensional topological insulator (2DTI) Ta2Ni3Te5 material.
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Affiliation(s)
- Kamal Harrison
- NanoScience Technology Center and Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Dylan A Jeff
- NanoScience Technology Center and Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Jonathan M DeStefano
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Olivia Peek
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Akihiro Kushima
- Department of Materials Science and Engineering, and Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, Florida 32816, United States
| | - Jiun-Haw Chu
- Department of Physics, University of Washington, Seattle, Washington 98195, United States
| | - Humberto R Gutiérrez
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Saiful I Khondaker
- NanoScience Technology Center and Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
- School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32826, United States
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13
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Guillet T, Galceran R, Sierra JF, Belarre FJ, Ballesteros B, Costache MV, Dosenovic D, Okuno H, Marty A, Jamet M, Bonell F, Valenzuela SO. Spin-Orbit Torques and Magnetization Switching in (Bi,Sb) 2Te 3/Fe 3GeTe 2 Heterostructures Grown by Molecular Beam Epitaxy. Nano Lett 2024; 24:822-828. [PMID: 38263950 DOI: 10.1021/acs.nanolett.3c03291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Topological insulators (TIs) hold promise for manipulating the magnetization of a ferromagnet (FM) through the spin-orbit torque (SOT) mechanism. However, integrating TIs with conventional FMs often leads to significant device-to-device variations and a broad distribution of SOT magnitudes. In this work, we present a scalable approach to grow a full van der Waals FM/TI heterostructure by molecular beam epitaxy, combining the charge-compensated TI (Bi,Sb)2Te3 with 2D FM Fe3GeTe2 (FGT). Harmonic magnetotransport measurements reveal that the SOT efficiency exhibits a non-monotonic temperature dependence and experiences a substantial enhancement with a reduction of the FGT thickness to 2 monolayers. Our study further demonstrates that the magnetization of ultrathin FGT films can be switched with a current density of Jc ∼ 1010 A/m2, with minimal device-to-device variations compared to previous investigations involving traditional FMs.
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Affiliation(s)
- Thomas Guillet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Regina Galceran
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Juan F Sierra
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Francisco J Belarre
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Belén Ballesteros
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Marius V Costache
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | | | - Hanako Okuno
- Univ. Grenoble Alpes, CEA, IRIG-MEM, 38000 Grenoble, France
| | - Alain Marty
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Matthieu Jamet
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Frédéric Bonell
- Univ. Grenoble Alpes, CEA, CNRS, Grenoble INP, IRIG-SPINTEC, 38000 Grenoble, France
| | - Sergio O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology (BIST), Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08070 Barcelona, Spain
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14
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Zhang M, Huang H, Li J, Wu Q. ZNF143 deletion alters enhancer/promoter looping and CTCF/cohesin geometry. Cell Rep 2024; 43:113663. [PMID: 38206813 DOI: 10.1016/j.celrep.2023.113663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/28/2023] [Accepted: 12/22/2023] [Indexed: 01/13/2024] Open
Abstract
The transcription factor ZNF143 contains a central domain of seven zinc fingers in a tandem array and is involved in 3D genome construction. However, the mechanism by which ZNF143 functions in chromatin looping remains unclear. Here, we show that ZNF143 directionally recognizes a diverse range of genomic sites directly within enhancers and promoters and is required for chromatin looping between these sites. In addition, ZNF143 is located between CTCF and cohesin at numerous CTCF sites, and ZNF143 removal narrows the space between CTCF and cohesin. Moreover, genetic deletion of ZNF143, in conjunction with acute CTCF degradation, reveals that ZNF143 and CTCF collaborate to regulate higher-order topological chromatin organization. Finally, CTCF depletion enlarges direct ZNF143 chromatin looping. Thus, ZNF143 is recruited by CTCF to the CTCF sites to regulate CTCF/cohesin configuration and TAD (topologically associating domain) formation, whereas directional recognition of genomic DNA motifs directly by ZNF143 itself regulates promoter activity via chromatin looping.
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Affiliation(s)
- Mo Zhang
- Center for Comparative Biomedicine, Ministry of Education Key Laboratory of Systems Biomedicine, State Key Laboratory of Medical Genomics, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China; WLA Laboratories, Shanghai 201203, China
| | - Haiyan Huang
- Center for Comparative Biomedicine, Ministry of Education Key Laboratory of Systems Biomedicine, State Key Laboratory of Medical Genomics, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China; WLA Laboratories, Shanghai 201203, China
| | - Jingwei Li
- Center for Comparative Biomedicine, Ministry of Education Key Laboratory of Systems Biomedicine, State Key Laboratory of Medical Genomics, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China; WLA Laboratories, Shanghai 201203, China
| | - Qiang Wu
- Center for Comparative Biomedicine, Ministry of Education Key Laboratory of Systems Biomedicine, State Key Laboratory of Medical Genomics, Institute of Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, China; WLA Laboratories, Shanghai 201203, China.
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15
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Gultom P, Hsu CC, Lee MK, Su SH, Huang JCA. Epitaxial Growth and Characterization of Nanoscale Magnetic Topological Insulators: Cr-Doped (Bi 0.4Sb 0.6) 2Te 3. Nanomaterials (Basel) 2024; 14:157. [PMID: 38251122 PMCID: PMC10821443 DOI: 10.3390/nano14020157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/30/2023] [Accepted: 01/07/2024] [Indexed: 01/23/2024]
Abstract
The exploration initiated by the discovery of the topological insulator (BixSb1-x)2Te3 has extended to unlock the potential of quantum anomalous Hall effects (QAHEs), marking a revolutionary era for topological quantum devices, low-power electronics, and spintronic applications. In this study, we present the epitaxial growth of Cr-doped (Bi0.4Sb0.6)2Te3 (Cr:BST) thin films via molecular beam epitaxy, incorporating various Cr doping concentrations with varying Cr/Sb ratios (0.025, 0.05, 0.075, and 0.1). High-quality crystalline of the Cr:BST thin films deposited on a c-plane sapphire substrate has been rigorously confirmed through reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) analyses. The existence of a Cr dopant has been identified with a reduction in the lattice parameter of BST from 30.53 ± 0.05 to 30.06 ± 0.04 Å confirmed by X-ray diffraction, and the valence state of Cr verified by X-ray photoemission (XPS) at binding energies of ~573.1 and ~583.5 eV. Additionally, the influence of Cr doping on lattice vibration was qualitatively examined by Raman spectroscopy, revealing a blue shift in peaks with increased Cr concentration. Surface characteristics, crucial for the functionality of topological insulators, were explored via Atomic Force Microscopy (AFM), illustrating a sevenfold reduction in surface roughness as the Cr concentration increased from 0 to 0.1. The ferromagnetic properties of Cr:BST were examined by a superconducting quantum interference device (SQUID) with a magnetic field applied in out-of-plane and in-plane directions. The Cr:BST samples exhibited a Curie temperature (Tc) above 50 K, accompanied by increased magnetization and coercivity with increasing Cr doping levels. The introduction of the Cr dopant induces a transition from n-type ((Bi0.4Sb0.6)2Te3) to p-type (Cr:(Bi0.4Sb0.6)2Te3) carriers, demonstrating a remarkable suppression of carrier density up to one order of magnitude, concurrently enhancing carrier mobility up to a factor of 5. This pivotal outcome is poised to significantly influence the development of QAHE studies and spintronic applications.
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Affiliation(s)
- Pangihutan Gultom
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (P.G.); (C.-C.H.)
| | - Chia-Chieh Hsu
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (P.G.); (C.-C.H.)
| | - Min Kai Lee
- Instrument Division, Core Facility Center, National Cheng Kung University, Tainan 701, Taiwan;
| | - Shu Hsuan Su
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (P.G.); (C.-C.H.)
| | - Jung-Chung-Andrew Huang
- Department of Physics, National Cheng Kung University, Tainan 701, Taiwan; (P.G.); (C.-C.H.)
- Instrument Division, Core Facility Center, National Cheng Kung University, Tainan 701, Taiwan;
- Department of Applied Physics, National Kaohsiung University, Kaohsiung 811, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, Ministry of Science and Technology, Taipei 10601, Taiwan
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16
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Lohmann M, Wickramaratne D, Moon J, Noyan M, Chuang HJ, Jonker BT, Li CH. Highly Efficient Spin-Orbit Torque Switching in Bi 2Se 3/Fe 3GeTe 2 van der Waals Heterostructures. ACS Nano 2024; 18:680-690. [PMID: 38109771 DOI: 10.1021/acsnano.3c09041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2023]
Abstract
Topological insulators (TIs) have shown promise as a spin-generating layer to switch the magnetization state of ferromagnets via spin-orbit torque (SOT) due to charge-to-spin conversion efficiency of the TI surface states that arises from spin-momentum locking. However, when TIs are interfaced with conventional bulk ferromagnetic metals, the combination of charge transfer and hybridization can potentially destroy the spin texture and hamper the possibility of accessing the TI surface states. Here, we fabricate an all van der Waals (vdW) heterostructure consisting of molecular beam epitaxy grown bulk-insulating Bi2Se3 and exfoliated 2D metallic ferromagnet Fe3GeTe2 (FGT) with perpendicular anisotropy. By detecting the magnetization state of the FGT via anomalous Hall effect and magneto-optical Kerr effect measurements, we determine the critical switching current density for magnetization switching to be Jc ≈ 1.2 × 106 A/cm2, the lowest reported for the switching of a perpendicular anisotropy ferromagnet using Bi2Se3. From second harmonic Hall measurements, we further determine the SOT efficiency (ξDL) to be in the range of 1.8 ± 0.3 and 1.4 ± 0.08 between 5 and 150 K, comparable to the highest values reported for Bi2Se3. Our density functional theory calculations find that the weak interlayer interactions at the Bi2Se3/FGT interface lead to a weakened dipole at the interface and suppress the proximity induced magnetic moment on Bi2Se3. This enables direct access to the TI surface states contributed by the first quintuple layer, where the spins are singly degenerate with significant net in-plane spin polarization. Our results highlight the clear advantage of all-vdW heterostructures with weak interlayer interactions that can enhance SOT efficiency and minimize critical current density, an important step toward realizing next generation low-power nonvolatile memory and spintronic devices.
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Affiliation(s)
- Mark Lohmann
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
- American Society for Engineering Education, Washington, D.C. 20036, United States
| | - Darshana Wickramaratne
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Jisoo Moon
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
- National Research Council, Washington, D.C. 20001, United States
| | - Mehmet Noyan
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Hsun-Jen Chuang
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Berend T Jonker
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Connie H Li
- Materials Science and Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
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17
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Wei XK, Jalil AR, Rüßmann P, Ando Y, Grützmacher D, Blügel S, Mayer J. Atomic Diffusion-Induced Polarization and Superconductivity in Topological Insulator-Based Heterostructures. ACS Nano 2024; 18:571-580. [PMID: 38126781 PMCID: PMC10786152 DOI: 10.1021/acsnano.3c08601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
The proximity effect at a highly transparent interface of an s-wave superconductor (S) and a topological insulator (TI) provides a promising platform to create Majorana zero modes in artificially designed heterostructures. However, structural and chemical issues pertinent to such interfaces have been poorly explored so far. Here, we report the discovery of Pd diffusion-induced polarization at interfaces between superconductive Pd1+x(Bi0.4Te0.6)2 (xPBT, 0 ≤ x ≤ 1) and Pd-intercalated Bi2Te3 by using atomic-resolution scanning transmission electron microscopy. Our quantitative image analysis reveals that nanoscale lattice strain and QL polarity synergistically suppress and promote Pd diffusion at the normal and parallel interfaces, formed between Te-Pd-Bi triple layers (TLs) and Te-Bi-Te-Bi-Te quintuple layers (QLs), respectively. Further, our first-principles calculations unveil that the superconductivity of the xPBT phase and topological nature of the Pd-intercalated Bi2Te3 phase are robust against the broken inversion symmetry. These findings point out the necessity of considering the coexistence of electric polarization with superconductivity and topology in such S-TI systems.
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Affiliation(s)
- Xian-Kui Wei
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Abdur Rehman Jalil
- Peter
Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Philipp Rüßmann
- Institute
for Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
- Peter
Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich GmbH and JARA, 52425 Jülich, Germany
| | - Yoichi Ando
- Physics
Institute II, University of Cologne, Zülpicher Straße 77, 50937 Köln, Germany
| | - Detlev Grützmacher
- Peter
Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stefan Blügel
- Peter
Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich GmbH and JARA, 52425 Jülich, Germany
| | - Joachim Mayer
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Central
Facility for Electron Microscopy, RWTH Aachen
University, Ahornstraße
55, 52074 Aachen, Germany
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18
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Maier P, Hourigan NJ, Ruckhofer A, Bremholm M, Tamtögl A. Surface properties of 1T-TaS 2 and contrasting its electron-phonon coupling with TlBiTe 2 from helium atom scattering. Front Chem 2023; 11:1249290. [PMID: 38033467 PMCID: PMC10687202 DOI: 10.3389/fchem.2023.1249290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/19/2023] [Indexed: 12/02/2023] Open
Abstract
We present a detailed helium atom scattering study of the charge-density wave (CDW) system and transition metal dichalcogenide 1T-TaS2. In terms of energy dissipation, we determine the electron-phonon (e-ph) coupling, a quantity that is at the heart of conventional superconductivity and may even "drive" phase transitions such as CDWs. The e-ph coupling of TaS2 in the commensurate CDW phase (λ = 0.59 ± 0.12) is compared with measurements of the topo-logical insulator TlBiTe2 (λ = 0.09 ± 0.01). Furthermore, by means of elastic He diffraction and resonance/interference effects in He scattering, the thermal expansion of the surface lattice, the surface step height, and the three-dimensional atom-surface interaction potential are determined including the electronic corrugation of 1T-TaS2. The linear thermal expansion coefficient is similar to that of other transition-metal dichalcogenides. The He-TaS2 interaction is best described by a corrugated Morse potential with a relatively large well depth and supports a large number of bound states, comparable to the surface of Bi2Se3, and the surface electronic corrugation of 1T-TaS2 is similar to the ones found for semimetal surfaces.
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Affiliation(s)
- Philipp Maier
- Institute of Experimental Physics, Graz University of Technology, Graz, Austria
| | - Noah. J. Hourigan
- Institute of Experimental Physics, Graz University of Technology, Graz, Austria
| | - Adrian Ruckhofer
- Institute of Experimental Physics, Graz University of Technology, Graz, Austria
| | - Martin Bremholm
- Department of Chemistry and iNANO, Aarhus University, Aarhus, Denmark
| | - Anton Tamtögl
- Institute of Experimental Physics, Graz University of Technology, Graz, Austria
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19
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Kim J, Kim D, Kim DE, Chacón A. Circular dichroism in Floquet Chern insulator via high-order harmonics spectroscopy. J Phys Condens Matter 2023; 36:035701. [PMID: 37860915 DOI: 10.1088/1361-648x/ad0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/04/2023] [Indexed: 10/21/2023]
Abstract
High-order harmonics (HOHs) spectroscopy is attracting the attention of the condensed matter community, mostly because the HOHs spectrum encode the material property. Topological materials are of interest for both basic research and advanced technologies because of their robust properties against dissipation and perturbations. Floquet engineering technique have been demonstrated to be a unique tool to manipulate topological phase. In this paper, we apply HOH spectroscopy to characterize the Floquet state via the circular dichroism (CD). We find that the CD of the co-rotating harmonics is sensitive to Floquet topological states.
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Affiliation(s)
- Jeail Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, 77, Pohang 37673, Republic of Korea
- Max Planck POSTECH/KOREA Research Initiative, Pohang 37673, Republic of Korea
| | - Dasol Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, 77, Pohang 37673, Republic of Korea
- Max Planck POSTECH/KOREA Research Initiative, Pohang 37673, Republic of Korea
| | - Dong Eon Kim
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, 77, Pohang 37673, Republic of Korea
- Max Planck POSTECH/KOREA Research Initiative, Pohang 37673, Republic of Korea
| | - Alexis Chacón
- Department of Physics and Center for Attosecond Science and Technology, POSTECH, 77, Pohang 37673, Republic of Korea
- Max Planck POSTECH/KOREA Research Initiative, Pohang 37673, Republic of Korea
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20
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Thanopulos I, Yannopapas V, Paspalakis E. Strong Coupling Dynamics of a Quantum Emitter near a Topological Insulator Nanoparticle. Nanomaterials (Basel) 2023; 13:2787. [PMID: 37887938 PMCID: PMC10609747 DOI: 10.3390/nano13202787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 09/11/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023]
Abstract
We study the spontaneous emission dynamics of a quantum emitter near a topological insulator Bi2Se3 spherical nanoparticle. Using the electromagnetic Green's tensor method, we find exceptional Purcell factors of the quantum emitter up to 1010 at distances between the emitter and the nanoparticle as large as half the nanoparticle's radius in the terahertz regime. We study the spontaneous emission evolution of a quantum emitter for various transition frequencies in the terahertz and various vacuum decay rates. For short vacuum decay times, we observe non-Markovian spontaneous emission dynamics, which correspond perfectly to values of well-established measures of non-Markovianity and possibly indicate considerable dynamical quantum speedup. The dynamics turn progressively Markovian as the vacuum decay times increase, while in this regime, the non-Markovianity measures are nullified, and the quantum speedup vanishes. For the shortest vacuum decay times, we find that the population remains trapped in the emitter, which indicates that a hybrid bound state between the quantum emitter and the continuum of electromagnetic modes as affected by the nanoparticle has been formed. This work demonstrates that a Bi2Se3 spherical nanoparticle can be a nanoscale platform for strong light-matter coupling.
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Affiliation(s)
- Ioannis Thanopulos
- Materials Science Department, School of Natural Sciences, University of Patras, 265 04 Patras, Greece;
| | - Vassilios Yannopapas
- Department of Physics, National Technical University of Athens, 157 80 Athens, Greece;
| | - Emmanuel Paspalakis
- Materials Science Department, School of Natural Sciences, University of Patras, 265 04 Patras, Greece;
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21
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Marchenkov VV, Lukoyanov AV, Baidak ST, Perevalova AN, Fominykh BM, Naumov SV, Marchenkova EB. Electronic Structure and Transport Properties of Bi 2Te 3 and Bi 2Se 3 Single Crystals. Micromachines (Basel) 2023; 14:1888. [PMID: 37893325 PMCID: PMC10609277 DOI: 10.3390/mi14101888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023]
Abstract
The electrical resistivity and the Hall effect of topological insulator Bi2Te3 and Bi2Se3 single crystals were studied in the temperature range from 4.2 to 300 K and in magnetic fields up to 10 T. Theoretical calculations of the electronic structure of these compounds were carried out in density functional approach, taking into account spin-orbit coupling and crystal structure data for temperatures of 5, 50 and 300 K. A clear correlation was found between the density of electronic states at the Fermi level and the current carrier concentration. In the case of Bi2Te3, the density of states at the Fermi level and the current carrier concentration increase with increasing temperature, from 0.296 states eV-1 cell-1 (5 K) to 0.307 states eV-1 cell-1 (300 K) and from 0.9 × 1019 cm-3 (5 K) to 2.6 × 1019 cm-3 (300 K), respectively. On the contrary, in the case of Bi2Se3, the density of states decreases with increasing temperature, from 0.201 states eV-1 cell-1 (5 K) to 0.198 states eV-1 cell-1 (300 K), and, as a consequence, the charge carrier concentration also decreases from 2.94 × 1019 cm-3 (5 K) to 2.81 × 1019 cm-3 (300 K).
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Affiliation(s)
- Vyacheslav V. Marchenkov
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
- Institute of Physics and Technology, Ural Federal University Named after the First President of Russia B.N. Yeltsin, 620002 Ekaterinburg, Russia
| | - Alexey V. Lukoyanov
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
- Institute of Physics and Technology, Ural Federal University Named after the First President of Russia B.N. Yeltsin, 620002 Ekaterinburg, Russia
| | - Semyon T. Baidak
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
- Institute of Physics and Technology, Ural Federal University Named after the First President of Russia B.N. Yeltsin, 620002 Ekaterinburg, Russia
| | - Alexandra N. Perevalova
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
| | - Bogdan M. Fominykh
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
- Institute of Physics and Technology, Ural Federal University Named after the First President of Russia B.N. Yeltsin, 620002 Ekaterinburg, Russia
| | - Sergey V. Naumov
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
| | - Elena B. Marchenkova
- M.N. Mikheev Institute of Metal Physics of Ural Branch of Russian Academy of Sciences, 620108 Ekaterinburg, Russia; (V.V.M.); (S.T.B.); (A.N.P.); (B.M.F.); (S.V.N.); (E.B.M.)
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22
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Fedoseev AD. Modification of topological corner excitations at the interplay of boundary geometry and Coulomb interaction. J Phys Condens Matter 2023; 35:455301. [PMID: 37549671 DOI: 10.1088/1361-648x/aceddf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/07/2023] [Indexed: 08/09/2023]
Abstract
The effect of Coulomb interaction on the 2D second order topological superconductor is investigated taking into account different geometries of the boundary in the mainframe of the mean-field approximation. The spontaneous symmetry breaking, described earlier in Aksenovet al(2023Phys. Rev.B107125401), is found to be robust against the boundary deformation. Meanwhile, the details of the state with spontaneously broken symmetry is found to be dependent on the specific boundary geometry. Considering different types of the boundary of the 2D system, it is demonstrated that the deviation of the electron density in the broken symmetry state is determined by the position of the zero-dimensional (second-order) excitations with nearly zero energy. The critical value of the Coulomb interaction, at which the transition occurs, is found to be determined by the energy of these excitations, which is non-zero due to overlapping of the wave-functions at different corners.
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Affiliation(s)
- A D Fedoseev
- Kirensky Institute of Physics, Federal Research Center KSC SB RAS, Akademgorodok 50/38, 660036 Krasnoyarsk, Russia
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23
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Sahu P, Yang Y, Fan Y, Jaffrès H, Chen JY, Devaux X, Fagot-Revurat Y, Migot S, Rongione E, Chen T, Abel Dainone P, George JM, Dhillon S, Micica M, Lu Y, Wang JP. Room Temperature Spin-to-Charge Conversion in Amorphous Topological Insulating Gd-Alloyed Bi xSe 1-x/CoFeB Bilayers. ACS Appl Mater Interfaces 2023; 15:38592-38602. [PMID: 37550946 DOI: 10.1021/acsami.3c07695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/09/2023]
Abstract
Disordered topological insulator (TI) films have gained intense interest by benefiting from both the TI's exotic transport properties and the advantage of mass production by sputtering. Here, we report on the clear evidence of spin-charge conversion (SCC) in amorphous Gd-alloyed BixSe1-x (BSG)/CoFeB bilayers fabricated by sputtering, which could be related to the amorphous TI surface states. Two methods have been employed to study SCC in BSG (tBSG = 6-16 nm)/CoFeB(5 nm) bilayers with different BSG thicknesses. First, spin pumping is used to generate a spin current in CoFeB and detect SCC by the inverse Edelstein effect (IEE). The maximum SCC efficiency (SCE) is measured to be as large as 0.035 nm (IEE length λIEE) in a 6 nm thick BSG sample, which shows a strong decay when tBSG increases due to the increase of BSG surface roughness. The second method is THz time-domain spectroscopy, which reveals a small tBSG dependence of SCE, validating the occurrence of a pure interface state-related SCC. Furthermore, our angle-resolved photoemission spectroscopy data show dispersive two-dimensional surface states that cross the bulk gap until the Fermi level, strengthening the possibility of SCC due to the amorphous TI states. Our studies provide a new experimental direction toward the search for topological systems in amorphous solids.
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Affiliation(s)
- Protyush Sahu
- School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Yifei Yang
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Yihong Fan
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Henri Jaffrès
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Jun-Yang Chen
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
| | - Xavier Devaux
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Yannick Fagot-Revurat
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Sylvie Migot
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Enzo Rongione
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Tongxin Chen
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Pambiang Abel Dainone
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Jean-Marie George
- Unité Mixte de Physique, CNRS, Thales, Université Paris-Saclay, 91767 Palaiseau, France
| | - Sukhdeep Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Martin Micica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, F-75005 Paris, France
| | - Yuan Lu
- Institut Jean Lamour, Université de Lorraine, CNRS, UMR 7198, Campus ARTEM, 2 Allée André Guinier, 54011 Nancy, France
| | - Jian-Ping Wang
- School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, Minnesota 55455, United States
- Department of Electrical and Computer Engineering, University of Minnesota, 200 Union Street SE, Minneapolis, Minnesota 55455, United States
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24
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Thenapparambil A, Dos Santos GE, Li CA, Abdelghany M, Beugeling W, Buhmann H, Gould C, Zhang SB, Trauzettel B, Molenkamp LW. Fluctuations in Planar Magnetotransport Due to Tilted Dirac Cones in Topological Materials. Nano Lett 2023; 23:6914-6919. [PMID: 37498076 DOI: 10.1021/acs.nanolett.3c01508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Fluctuations in planar magnetotransport are ubiquitous in topological HgTe structures, in both tensile (topological insulator) and compressively strained layers (Weyl semimetal phase). We show that the common reason for the fluctuations is the presence of tilted Dirac cones combined with the formation of charge puddles. The origin of the tilted Dirac cones is the mix of the Zeeman term due to the in-plane magnetic field and quadratic contributions to the dispersion relation. We develop a network model that mimics the transport of tilted Dirac fermions in the landscape of charge puddles. The model captures the essential features of the experimental data. It should be relevant for the interpretation of planar magnetotransport in a variety of topological and small band gap materials.
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Affiliation(s)
- Arya Thenapparambil
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
| | - Graciely Elias Dos Santos
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
| | - Chang-An Li
- Faculty for Physics and Astronomy (TP4), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Mohamed Abdelghany
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
| | - Wouter Beugeling
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
| | - Hartmut Buhmann
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
| | - Charles Gould
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
| | - Song-Bo Zhang
- Department of Physics, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Björn Trauzettel
- Faculty for Physics and Astronomy (TP4), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Laurens W Molenkamp
- Faculty for Physics and Astronomy (EP3), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany
- Institute for Topological Insulators, Am Hubland, D-97074 Würzburg, Germany
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25
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Yar A, Taif Usman M, Sabeeh K. Tuning the spin of Dirac fermions on the surface of topological insulators in proximity to a helical spin density wave. J Phys Condens Matter 2023; 35. [PMID: 37550989 DOI: 10.1088/1361-648x/acebaa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 07/28/2023] [Indexed: 08/09/2023]
Abstract
We investigate the spin tunability of Dirac fermions on the surface of a 3D topological insulator in proximity to a helical spin density wave, acting as an applied one-dimensional periodic potential for spins produced by spiral multiferroic oxide. It is observed that the spin mean values of Dirac fermion undergo oscillations under the influence of such a periodic potential created by the exchange field of magnetization. The tunability of spin is strongly affected by the strength, orientation and period of the exchange field. In particular, the mean values of spin are anisotropic around the Dirac point, depending strongly on the amplitude and spatial period of the periodic potential. We also find that the spin expectation values change significantly by changing the plane of magnetization. Interestingly, the in-plane components of spin mean values perform pronounced oscillations, whereas the out of plane component does not oscillate at all. The oscillations of planar components of spin are originated from the spin-momentum locking on the surface of topological insulator.
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Affiliation(s)
- Abdullah Yar
- Department of Physics, Kohat University of Science and Technology, Kohat 26000, Khyber Pakhtunkhwa, Pakistan
| | - Muhammad Taif Usman
- Department of Physics, Kohat University of Science and Technology, Kohat 26000, Khyber Pakhtunkhwa, Pakistan
| | - Kashif Sabeeh
- Department of Physics, Quaid-i-Azam University, Islamabad 45320, Pakistan
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26
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Assi DS, Huang H, Karthikeyan V, Theja VCS, de Souza MM, Xi N, Li WJ, Roy VAL. Quantum Topological Neuristors for Advanced Neuromorphic Intelligent Systems. Adv Sci (Weinh) 2023; 10:e2300791. [PMID: 37340871 PMCID: PMC10460853 DOI: 10.1002/advs.202300791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/02/2023] [Indexed: 06/22/2023]
Abstract
Neuromorphic artificial intelligence systems are the future of ultrahigh performance computing clusters to overcome complex scientific and economical challenges. Despite their importance, the advancement in quantum neuromorphic systems is slow without specific device design. To elucidate biomimicking mammalian brain synapses, a new class of quantum topological neuristors (QTN) with ultralow energy consumption (pJ) and higher switching speed (µs) is introduced. Bioinspired neural network characteristics of QTNs are the effects of edge state transport and tunable energy gap in the quantum topological insulator (QTI) materials. With augmented device and QTI material design, top notch neuromorphic behavior with effective learning-relearning-forgetting stages is demonstrated. Critically, to emulate the real-time neuromorphic efficiency, training of the QTNs is demonstrated with simple hand gesture game by interfacing them with artificial neural networks to perform decision-making operations. Strategically, the QTNs prove the possession of incomparable potential to realize next-gen neuromorphic computing for the development of intelligent machines and humanoids.
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Affiliation(s)
- Dani S. Assi
- Electronics and Nanoscale EngineeringJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUK
| | - Hongli Huang
- Electronics and Nanoscale EngineeringJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUK
| | - Vaithinathan Karthikeyan
- Electronics and Nanoscale EngineeringJames Watt School of EngineeringUniversity of GlasgowGlasgowG12 8QQUK
| | - Vaskuri C. S. Theja
- Materials Science and EngineeringCity University of Hong KongTat Chee AvenueHong KongHong Kong
| | | | - Ning Xi
- Industrial and Manufacturing Systems EngineeringThe University of Hong KongPokfulam RoadHong KongHong Kong
| | - Wen Jung Li
- Mechanical EngineeringCity University of Hong KongTat Chee AvenueHong KongHong Kong
| | - Vellaisamy A. L. Roy
- School of Science and TechnologyHong Kong Metropolitan UniversityHo Man TinHong KongHong Kong
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27
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Lee T, Jeon GS. Exchange Couplings and Edge States in Two-Dimensional Topological Insulators. J Phys Condens Matter 2023. [PMID: 37463587 DOI: 10.1088/1361-648x/ace870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
We consider two-dimensional honeycomb-lattice topological insulators of electrons which are exposed to exchange couplings at the edges, paying particular attention to the energy dispersions of edge states. The energy band structure of edge states is found to depend strongly on the direction of exchange couplings. Energy band splitting occurs for the exchange couplings perpendicular to the plane of topological insulators. In contrast, the parallel exchange couplings turn out to generate a finite energy gap in the edge-state bands for zigzag edges while armchair nanoribbons does not show such energy gaps. We also discuss the dependence of energy band structures of edge states on the magnetic structure of exchange couplings as well as the disorder effects on the edge-state density of states.
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Affiliation(s)
- Teresa Lee
- Physics, Ewha Womans University, Department of Physics, Ewha Womans University, 52 Ewhayeodae-Gil, Seodaemun-Gu, Seoul, Republic of Korea, Seoul, 03760, Korea (the Republic of)
| | - Gun Sang Jeon
- Physics, Ewha Womans University, Department of Physics, Ewha Womans University, 52 Ewhayeodae-Gil, Seodaemun-Gu, Seoul, Republic of Korea, Seoul, 03760, Korea (the Republic of)
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28
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Babich I, Kudriashov A, Baranov D, Stolyarov VS. Limitations of the Current-Phase Relation Measurements by an Asymmetric dc-SQUID. Nano Lett 2023. [PMID: 37428644 DOI: 10.1021/acs.nanolett.3c01970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
Exotic quantum transport phenomena established in Josephson junctions (JJs) are reflected by a nonsinusoidal current-phase relation (CPR). The solidified approach to measuring the CPR is via an asymmetric dc-SQUID with a reference JJ that has a high critical current. We probed this method by measuring CPRs of hybrid JJs based on the 3D topological insulator (TI) Bi2Te2Se with a nanobridge acting as a reference JJ. We captured both highly skewed and sinusoidal critical current oscillations within single devices which contradict the uniqueness of the CPR. This implies that the widely used method provides inaccurate CPR measurement and leads to misinterpretation. It was shown that the accuracy of the CPR measurement is mediated by the asymmetry in derivatives of the CPRs but not in critical currents, as was previously thought. Finally, we provided considerations for an accurate CPR measurement via the most commonly used reference JJs.
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Affiliation(s)
- Ian Babich
- Advanced Mesoscience and Nanotechnology Centre, Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Russia
| | - Andrei Kudriashov
- Advanced Mesoscience and Nanotechnology Centre, Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Russia
| | - Denis Baranov
- Advanced Mesoscience and Nanotechnology Centre, Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Russia
| | - Vasily S Stolyarov
- Advanced Mesoscience and Nanotechnology Centre, Moscow Institute of Physics and Technology, 141700, Dolgoprudny, Russia
- National University of Science and Technology MISIS, 119049 Moscow, Russia
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29
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Liang Z, Wang Q, Ma J, Liu J, Wang S, Qiao S. Self-Powered Bi 2Se 3/Si Position-Sensitive Detector and Its Performance Enhancement by Introducing a Si Nanopyramid Structure. ACS Appl Mater Interfaces 2023. [PMID: 37218801 DOI: 10.1021/acsami.3c05357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bi2Se3, as a novel 3D topological insulator (TI), is expected to be a strong candidate for next-generation optoelectronic devices due to its intriguing optical and electrical properties. In this study, a series of Bi2Se3 films with different thicknesses of 5-40 nm were successfully prepared on planar-Si substrates and developed as self-powered light position-sensitive detectors (PSDs) by introducing lateral photovoltaic effect (LPE). It is demonstrated that the Bi2Se3/planar-Si heterojunction shows a broad-band response range of 450-1064 nm, and the LPE response is strongly dependent on the Bi2Se3 layer thickness, which can be mainly attributed to the thickness-modulated longitudinal carrier separation and transport. The 15 nm thick PSD shows the best performance with a position sensitivity of up to 89.7 mV/mm, a nonlinearity of lower than 7%, and response time as fast as 62.6/49.4 μs. Moreover, to further enhance the LPE response, a novel Bi2Se3/pyramid-Si heterojunction is built by constructing a nanopyramid structure for the Si substrate. Owing to the improvement of the light absorption capability in the heterojunction, the position sensitivity is largely boosted up to 178.9 mV/mm, which gets an increment of 199% as compared with that of the Bi2Se3/planar-Si heterojunction device. At the same time, the nonlinearity is still kept within 10% as well due to the excellent conduction property of the Bi2Se3 film. In addition, an ultrafast response speed of 173/97.4 μs is also achieved in the newly proposed PSD with excellent stability and reproducibility. This result not only demonstrates the great potential of TIs in PSD but also provides a promising approach for tuning its performance.
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Affiliation(s)
- Zidong Liang
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China
| | - Qing Wang
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China
| | - Jikui Ma
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China
| | - Jihong Liu
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China
| | - Shufang Wang
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China
| | - Shuang Qiao
- Hebei Key Laboratory of Optic-Electronic Information and Materials, College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China
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30
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Pandey L, Husain S, Barwal V, Hait S, Gupta NK, Mishra V, Kumar N, Sharma N, Dixit D, Singh V, Chaudhary S. Topological transport properties of highly oriented Bi 2Te 3thin film deposited by sputtering. J Phys Condens Matter 2023. [PMID: 37172602 DOI: 10.1088/1361-648x/acd50a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Topological insulators (TIs) are the promising materials for next-generation technology due to their exotic features such as spin momentum locking, conducting surface states, etc. However, the high-quality growth of TIs by sputtering technique, which is one of the foremost industrial requirements, is extremely challenging. Also, the demonstration of simple investigation protocols to characterize topological properties of TIs using electron-transport methods is highly desirable. Here, we report the quantitative investigation of non-trivial parameters employing magnetotransport measurements on a prototypical highly textured Bi2Te3 TI thin film prepared by sputtering. Through the systematic analyses of the temperature and magnetic field dependent resistivity, all topological parameters associated with TIs, such as coherency factor (α), Berry phase (Φ_B), mass term (m), the dephasing parameter (p), slope of temperature dependent conductivity correction (κ) and the surface state penetration depth (λ) are estimated by using the modified 'Hikami-Larkin-Nagaoka', 'Lu-Shen' and 'Altshuler-Aronov' models. The obtained values of topological parameters are well comparable to those reported on molecular beam epitaxy grown TIs. The epitaxial growth of Bi2Te3 film using sputtering, and investigation of the non-trivial topological states from its electron-transport behaviour are important for their fundamental understanding and technological applications.
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Affiliation(s)
- Lalit Pandey
- Department of Physics, Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Sajid Husain
- Department of Physics, Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Vineet Barwal
- Department of Physics, Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Soumyarup Hait
- Department of Physics, Indian Institute of Technology Delhi, Thin film laboratory, New Delhi, Delhi, 110016, INDIA
| | - Nanhe Kumar Gupta
- Physics, Indian Institute of Technology Delhi, Thin Film Laboratory, IIT Delhi, New Delhi, Delhi, 110016, INDIA
| | - Vireshwar Mishra
- Department of Physics, Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Nakul Kumar
- Department of Physics, Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Nikita Sharma
- Department of Physics, Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Lib, IIT Delhi Hauz Khaz, NEW DELHI, Delhi, 110016, INDIA
| | - Dinesh Dixit
- Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Veer Singh
- Indian Institute of Technology Delhi, Main Building IIT Delhi near Central Library, IIT Delhi Hauz Khaz, NEW DELHI, DELHI, 110016, INDIA
| | - Sujeet Chaudhary
- Department of Physics, Indian Institute of Technology Delhi, Thin Film Laboratory, Hauz Khas, New Delhi 110016, New Delhi, Delhi, 110016, INDIA
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31
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Cho HD, Lee J, Kim DY, Chung SY, Lee JK. Enhanced Photoresponse of High Crystalline Bi 2Se 3 Thin-Films Using Patterned Substrates. ACS Appl Mater Interfaces 2023; 15:22274-22281. [PMID: 37115789 DOI: 10.1021/acsami.3c02501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
High-quality Bi2Se3 thin films with topological insulating properties at room temperature have recently attracted much attention as one of the promising materials for realizing innovative electronic and optoelectronic devices. Here, we report the high crystallinity growth of Bi2Se3 thin films on a patterned sapphire substrate (PSS) by using a vapor-phase transport deposition with minimizing thermal dissociation of Se atoms vaporized in Bi2Se3 powder. This PSS not only reduces the large dislocation of heterogeneously grown Bi2Se3 on a sapphire substrate but also induces enhanced light absorption in the visible to near-infrared (IR) ranges compared to Bi2Se3 on planar sapphire substrates. Thus, the Bi2Se3 thin film laterally grown on the PSS reveals uniform surface properties and high crystallinity in the rhombohedral lattice phase with a full width at half maximum of 0.06° for the XRD (003) peak. Also, the photoresponse of the fabricated IR conversion device using Bi2Se3/PSS heterostructure exhibits excellent performance and high reliability with no degradation after continuous switching. As a result, the device constructed with the Bi2Se3/PSS exhibits one order of magnitude higher NIR induced-photocurrent and 1-2 orders of magnitude faster photo-switching than that with Bi2Se3/Al2O3. Such an enhancement in the device performance of Bi2Se3/PSS is confirmed by the increased absorption spectra in visible and NIR ranges and the improved light absorption distribution.
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Affiliation(s)
- Hak Dong Cho
- Quantum Functional Semiconductor Research Center, Dongguk University, Seoul 04620, Korea
| | - Juwon Lee
- Quantum Functional Semiconductor Research Center, Dongguk University, Seoul 04620, Korea
| | - Deuk Young Kim
- Quantum Functional Semiconductor Research Center, Dongguk University, Seoul 04620, Korea
- Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Korea
| | - Sung Yun Chung
- Division of Energy and Optical Technology Convergence, Cheongju University, Cheongju-si, Chungcheongbuk-do 28503, Korea
| | - Jong-Kwon Lee
- Division of Energy and Optical Technology Convergence, Cheongju University, Cheongju-si, Chungcheongbuk-do 28503, Korea
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32
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Haris H, Jin TS, Batumalay M, Muhammad AR, Sampe J, Markom AM, Zain HA, Harun SW, Hasnan MMIM, Saad I. Single and Bunch Soliton Generation in Optical Fiber Lasers Using Bismuth Selenide Topological Insulator Saturable Absorber. Nanomaterials (Basel) 2023; 13:nano13091538. [PMID: 37177083 PMCID: PMC10180442 DOI: 10.3390/nano13091538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/08/2023] [Accepted: 04/21/2023] [Indexed: 05/15/2023]
Abstract
In this work, we present the generation of two distinct types of soliton pulses using a Bismuth Selenide (Bi2Se3) saturable absorber (SA) synthesized in our laboratory. The soliton pulses were generated in two different laser cavity configurations, resulting in two types of solitons: a soliton pulse with Kelly sidebands and a bunched soliton pulse with peak-dip sidebands. Both solitons operated at the fundamental repetition rate-23.3 MHz (for the soliton with Kelly sidebands) and 13 MHz (for the bunched soliton with peak-dip sidebands). We observed that the accumulation of nonlinear phase shift from the added single mode fiber (SMF) split the single soliton pulse into 44 pulses in a bunched oscillation envelope. At the same time, peak-dip sidebands were imposed on the bunched soliton spectrum due to constructive and destructive interferences between soliton pulse and dispersive waves. The measured pulse width for both solitons were 0.63 ps (for the soliton with Kelly sidebands) and 1.52 ps (for the bunched soliton with peak-dip sidebands), respectively. Our results demonstrate the potential of Bi2Se3 SAs in generating different types of soliton pulses, which could have potential applications in various areas of optical communication and spectroscopy.
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Affiliation(s)
- Hazlihan Haris
- Faculty of Engineering, Universiti Malaysia Sabah (UMS), Kota Kinabalu 88400, Sabah, Malaysia
| | - Tan Sin Jin
- School of Engineering, KDU University College, UOW Malaysia, Shah Alam 40150, Selangor, Malaysia
- KDU University College, UOW Malaysia, George Town 10400, Pulau Pinang, Malaysia
| | - Malathy Batumalay
- Faculty of Data Science & IT, INTI International University, Nilai 71800, Negeri Sembilan, Malaysia
| | - Ahmad Razif Muhammad
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi 43600, Selangor, Malaysia
| | - Jahariah Sampe
- Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi 43600, Selangor, Malaysia
| | - Arni Munira Markom
- School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
| | - Huda Adnan Zain
- Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Sulaiman Wadi Harun
- Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia
| | | | - Ismail Saad
- Faculty of Engineering, Universiti Malaysia Sabah (UMS), Kota Kinabalu 88400, Sabah, Malaysia
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33
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Rongione E, Baringthon L, She D, Patriarche G, Lebrun R, Lemaître A, Morassi M, Reyren N, Mičica M, Mangeney J, Tignon J, Bertran F, Dhillon S, Le Févre P, Jaffrès H, George JM. Spin-Momentum Locking and Ultrafast Spin-Charge Conversion in Ultrathin Epitaxial Bi 1 - x Sb x Topological Insulator. Adv Sci (Weinh) 2023:e2301124. [PMID: 37098646 DOI: 10.1002/advs.202301124] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 04/10/2023] [Indexed: 06/19/2023]
Abstract
The helicity of three-dimensional (3D) topological insulator surface states has drawn significant attention in spintronics owing to spin-momentum locking where the carriers' spin is oriented perpendicular to their momentum. This property can provide an efficient method to convert charge currents into spin currents, and vice-versa, through the Rashba-Edelstein effect. However, experimental signatures of these surface states to the spin-charge conversion are extremely difficult to disentangle from bulk state contributions. Here, spin- and angle-resolved photo-emission spectroscopy, and time-resolved THz emission spectroscopy are combined to categorically demonstrate that spin-charge conversion arises mainly from the surface state in Bi1 - x Sbx ultrathin films, down to few nanometers where confinement effects emerge. This large conversion efficiency is correlated, typically at the level of the bulk spin Hall effect from heavy metals, to the complex Fermi surface obtained from theoretical calculations of the inverse Rashba-Edelstein response. Both surface state robustness and sizeable conversion efficiency in epitaxial Bi1 - x Sbx thin films bring new perspectives for ultra-low power magnetic random-access memories and broadband THz generation.
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Affiliation(s)
- E Rongione
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Universitè Paris Cité, F-75005, Paris, France
| | - L Baringthon
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
- Université Paris-Saclay, Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, Saint-Aubin, F-91190, France
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, F-91120, France
| | - D She
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
- Université Paris-Saclay, Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, Saint-Aubin, F-91190, France
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, F-91120, France
| | - G Patriarche
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, F-91120, France
| | - R Lebrun
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
| | - A Lemaître
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, F-91120, France
| | - M Morassi
- Université Paris-Saclay, CNRS, Centre de Nanosciences et de Nanotechnologies, Palaiseau, F-91120, France
| | - N Reyren
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
| | - M Mičica
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Universitè Paris Cité, F-75005, Paris, France
| | - J Mangeney
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Universitè Paris Cité, F-75005, Paris, France
| | - J Tignon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Universitè Paris Cité, F-75005, Paris, France
| | - F Bertran
- Université Paris-Saclay, Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, Saint-Aubin, F-91190, France
| | - S Dhillon
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Universitè Paris Cité, F-75005, Paris, France
| | - P Le Févre
- Université Paris-Saclay, Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, Saint-Aubin, F-91190, France
| | - H Jaffrès
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
| | - J-M George
- Université Paris-Saclay, CNRS, Thales, Unité Mixte de Physique CNRS/Thales, F-91767, Palaiseau, France
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34
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Rößler M, Fan D, Münning F, Legg HF, Bliesener A, Lippertz G, Uday A, Yazdanpanah R, Feng J, Taskin A, Ando Y. Top-Down Fabrication of Bulk-Insulating Topological Insulator Nanowires for Quantum Devices. Nano Lett 2023; 23:2846-2853. [PMID: 36976857 DOI: 10.1021/acs.nanolett.3c00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In a nanowire (NW) of a three-dimensional topological insulator (TI), the quantum confinement of topological surface states leads to a peculiar sub-band structure that is useful for generating Majorana bound states. Top-down fabrication of TINWs from a high-quality thin film would be a scalable technology with great design flexibility, but there has been no report on top-down-fabricated TINWs where the chemical potential can be tuned to the charge neutrality point (CNP). Here we present a top-down fabrication process for bulk-insulating TINWs etched from high-quality (Bi1-xSbx)2Te3 thin films without degradation. We show that the chemical potential can be gate-tuned to the CNP, and the resistance of the NW presents characteristic oscillations as functions of the gate voltage and the parallel magnetic field, manifesting the TI-sub-band physics. We further demonstrate the superconducting proximity effect in these TINWs, preparing the groundwork for future devices to investigate Majorana bound states.
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Affiliation(s)
- Matthias Rößler
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Dingxun Fan
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Felix Münning
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Henry F Legg
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
| | - Andrea Bliesener
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Gertjan Lippertz
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
- KU Leuven, Quantum Solid State Physics, Celestijnenlaan 200 D, 3001 Leuven, Belgium
| | - Anjana Uday
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Roozbeh Yazdanpanah
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Junya Feng
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Alexey Taskin
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
| | - Yoichi Ando
- University of Cologne, Physics Institute II, Zülpicher Str. 77, 50937 Köln, Germany
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35
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Li H, Li Z. Quasi-periodic scattering of topological edge states induced by the vacancies in chloridized gallium bismuthide nanoribbons. J Phys Condens Matter 2023; 35:255302. [PMID: 36990103 DOI: 10.1088/1361-648x/acc8ae] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
The chloridized gallium bismuthide was predicted to be a two-dimensional topological insulator with large topological band gap. It may be beneficial for achieving the quantum spin Hall effect and its related applications at high temperatures. To better understand the quantum transport in topological nanoribbons, we investigated the effect of vacancy on the quantum transport of topological edge states in the armchair chloridized gallium bismuthide nanoribbons by combining density functional theory and nonequilibrium Green's function. The results suggest the vacancies at center are more likely to cause the scattering of topological edge states. The average scattering is insensitive to the enlargement of vacancy along the transport direction. More interestingly, the obvious scattering of topological edge states can only be found at some special energies, and these special energies are distributed quasi-periodically. The quasi-periodic scattering may be used as a kind of fingerprint of vacancies. Our studies may be helpful for the application of topological nanoribbons.
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Affiliation(s)
- Hangyu Li
- College of Science, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
| | - Zhongyao Li
- College of Science, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China
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36
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Tcakaev A, Rubrecht B, Facio JI, Zabolotnyy VB, Corredor LT, Folkers LC, Kochetkova E, Peixoto TRF, Kagerer P, Heinze S, Bentmann H, Green RJ, Gargiani P, Valvidares M, Weschke E, Haverkort MW, Reinert F, van den Brink J, Büchner B, Wolter AUB, Isaeva A, Hinkov V. Intermixing-Driven Surface and Bulk Ferromagnetism in the Quantum Anomalous Hall Candidate MnBi 6 Te 10. Adv Sci (Weinh) 2023; 10:e2203239. [PMID: 36802132 PMCID: PMC10074120 DOI: 10.1002/advs.202203239] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/17/2023] [Indexed: 06/18/2023]
Abstract
The recent realizations of the quantum anomalous Hall effect (QAHE) in MnBi2 Te4 and MnBi4 Te7 benchmark the (MnBi2 Te4 )(Bi2 Te3 )n family as a promising hotbed for further QAHE improvements. The family owes its potential to its ferromagnetically (FM) ordered MnBi2 Te4 septuple layers (SLs). However, the QAHE realization is complicated in MnBi2 Te4 and MnBi4 Te7 due to the substantial antiferromagnetic (AFM) coupling between the SLs. An FM state, advantageous for the QAHE, can be stabilized by interlacing the SLs with an increasing number n of Bi2 Te3 quintuple layers (QLs). However, the mechanisms driving the FM state and the number of necessary QLs are not understood, and the surface magnetism remains obscure. Here, robust FM properties in MnBi6 Te10 (n = 2) with Tc ≈ 12 K are demonstrated and their origin is established in the Mn/Bi intermixing phenomenon by a combined experimental and theoretical study. The measurements reveal a magnetically intact surface with a large magnetic moment, and with FM properties similar to the bulk. This investigation thus consolidates the MnBi6 Te10 system as perspective for the QAHE at elevated temperatures.
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Affiliation(s)
- Abdul‐Vakhab Tcakaev
- Physikalisches Institut (EP‐IV)Universität WürzburgAm HublandD‐97074WürzburgGermany
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
| | - Bastian Rubrecht
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
| | - Jorge I. Facio
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
- Centro Atómico BarilocheInstituto de Nanociencia y Nanotecnología (CNEA‐CONICET) and Instituto Balseiro. Av. Bustillo 9500Bariloche8400Argentina
| | - Volodymyr B. Zabolotnyy
- Physikalisches Institut (EP‐IV)Universität WürzburgAm HublandD‐97074WürzburgGermany
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
| | - Laura T. Corredor
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
| | - Laura C. Folkers
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Institut für Festkörper‐ und MaterialphysikTechnische Universität DresdenD‐01062DresdenGermany
| | - Ekaterina Kochetkova
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
| | - Thiago R. F. Peixoto
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Physikalisches Institut (EP‐VII)Universität WürzburgAm HublandD‐97074WürzburgGermany
| | - Philipp Kagerer
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Physikalisches Institut (EP‐VII)Universität WürzburgAm HublandD‐97074WürzburgGermany
| | - Simon Heinze
- Institute for Theoretical PhysicsHeidelberg UniversityPhilosophenweg 1969120HeidelbergGermany
| | - Hendrik Bentmann
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Physikalisches Institut (EP‐VII)Universität WürzburgAm HublandD‐97074WürzburgGermany
| | - Robert J. Green
- Department of Physics and Astronomy and Stewart Blusson Quantum Matter InstituteUniversity of British ColumbiaVancouverBritish ColumbiaV6T 1Z4Canada
- Department of Physics and Engineering PhysicsUniversity of SaskatchewanSaskatoonSKS7N 5E2Canada
| | - Pierluigi Gargiani
- ALBA Synchrotron Light SourceE‐08290 Cerdanyola del VallèsBarcelonaSpain
| | - Manuel Valvidares
- ALBA Synchrotron Light SourceE‐08290 Cerdanyola del VallèsBarcelonaSpain
| | - Eugen Weschke
- Helmholtz‐Zentrum Berlin für Materialien und EnergieAlbert‐Einstein‐Straße 15D‐12489BerlinGermany
| | - Maurits W. Haverkort
- Institute for Theoretical PhysicsHeidelberg UniversityPhilosophenweg 1969120HeidelbergGermany
| | - Friedrich Reinert
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Physikalisches Institut (EP‐VII)Universität WürzburgAm HublandD‐97074WürzburgGermany
| | - Jeroen van den Brink
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
- Institut für Theoretische PhysikTechnische Universität DresdenD‐01062DresdenGermany
| | - Bernd Büchner
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
- Institut für Festkörper‐ und MaterialphysikTechnische Universität DresdenD‐01062DresdenGermany
| | - Anja U. B. Wolter
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
| | - Anna Isaeva
- Leibniz Institut für Festkörper‐ und Werkstoffforschung (IFW) DresdenHelmholtzstraße 20D‐01069DresdenGermany
- Van der Waals‐Zeeman InstituteDepartment of Physics and AstronomyUniversity of AmsterdamScience Park 904Amsterdam1098 XHThe Netherlands
| | - Vladimir Hinkov
- Physikalisches Institut (EP‐IV)Universität WürzburgAm HublandD‐97074WürzburgGermany
- Würzburg‐Dresden Cluster of Excellence ct.qmatGermany
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Gracia-Abad R, Sangiao S, Kumar Chaluvadi S, Orgiani P, Teresa JMD. Ion-Induced Lateral Damage in the Focused Ion Beam Patterning of Topological Insulator Bi 2Se 3 Thin Films. Materials (Basel) 2023; 16:2244. [PMID: 36984129 PMCID: PMC10051711 DOI: 10.3390/ma16062244] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/03/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Focused Ion Beam patterning has become a widely applied technique in the last few decades in the micro- and nanofabrication of quantum materials, representing an important advantage in terms of resolution and versatility. However, ion irradiation can trigger undesired effects on the target material, most of them related to the damage created by the impinging ions that can severely affect the crystallinity of the sample, compromising the application of Focused Ion Beam to the fabrication of micro- and nanosized systems. We focus here on the case of Bi2Se3, a topological material whose unique properties rely on its crystallinity. In order to study the effects of ion irradiation on the structure of Bi2Se3, we irradiated with Ga+ ions the full width of Hall-bar devices made from thin films of this material, with the purpose of inducing changes in the electrical resistance and characterizing the damage created during the process. The results indicate that a relatively high ion dose is necessary to introduce significant changes in the conduction. This ion dose creates medium-range lateral damage in the structure, manifested through the formation of an amorphous region that can extend laterally up to few hundreds of nanometers beyond the irradiated area. This amorphous material is no longer expected to behave as intrinsic Bi2Se3, indicating a spatial limitation for the devices fabricated through this technique.
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Affiliation(s)
- Rubén Gracia-Abad
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Soraya Sangiao
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | | | - Pasquale Orgiani
- CNR-IOM, TASC Laboratory in Area Science Park, 34149 Trieste, Italy
| | - José María De Teresa
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza, Spain
- Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain
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Belec B, Kostevšek N, Pelle GD, Nemec S, Kralj S, Bergant Marušič M, Gardonio S, Fanetti M, Valant M. Silica Coated Bi 2Se 3 Topological Insulator Nanoparticles: An Alternative Route to Retain Their Optical Properties and Make Them Biocompatible. Nanomaterials (Basel) 2023; 13:809. [PMID: 36903688 PMCID: PMC10005201 DOI: 10.3390/nano13050809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/15/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
Localized surface plasmon resonance (LSPR) is the cause of the photo-thermal effect observed in topological insulator (TI) bismuth selenide (Bi2Se3) nanoparticles. These plasmonic properties, which are thought to be caused by its particular topological surface state (TSS), make the material interesting for application in the field of medical diagnosis and therapy. However, to be applied, the nanoparticles have to be coated with a protective surface layer, which prevents agglomeration and dissolution in the physiological medium. In this work, we investigated the possibility of using silica as a biocompatible coating for Bi2Se3 nanoparticles, instead of the commonly used ethylene-glycol, which, as is presented in this work, is not biocompatible and alters/masks the optical properties of TI. We successfully prepared Bi2Se3 nanoparticles coated with different silica layer thicknesses. Such nanoparticles, except those with a thick, ≈200 nm silica layer, retained their optical properties. Compared to ethylene-glycol coated nanoparticles, these silica coated nanoparticles displayed an improved photo-thermal conversion, which increased with the increasing thickness of the silica layer. To reach the desired temperatures, a 10-100 times lower concentration of photo-thermal nanoparticles was needed. In vitro experiments on erythrocytes and HeLa cells showed that, unlike ethylene glycol coated nanoparticles, silica coated nanoparticles are biocompatible.
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Affiliation(s)
- Blaž Belec
- Materials Research Laboratory, University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Nina Kostevšek
- Department for Nanostructured Materials, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Giulia Della Pelle
- Department for Nanostructured Materials, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Jožef Stefan International Postgraduate School, 1000 Ljubljana, Slovenia
| | - Sebastjan Nemec
- Department for Material Synthesis, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Slavko Kralj
- Department for Material Synthesis, Jožef Stefan Institute, 1000 Ljubljana, Slovenia
- Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Martina Bergant Marušič
- Laboratory for Environmental and Life Sciences, University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Sandra Gardonio
- Materials Research Laboratory, University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Mattia Fanetti
- Materials Research Laboratory, University of Nova Gorica, 5000 Nova Gorica, Slovenia
| | - Matjaž Valant
- Materials Research Laboratory, University of Nova Gorica, 5000 Nova Gorica, Slovenia
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Breindel AJ, Deng Y, Moir CM, Fang Y, Ran S, Lou H, Li S, Zeng Q, Shu L, Wolowiec CT, Schuller IK, Rosa PFS, Fisk Z, Singleton J, Maple MB. Probing FeSi, a d-electron topological Kondo insulator candidate, with magnetic field, pressure, and microwaves. Proc Natl Acad Sci U S A 2023; 120:e2216367120. [PMID: 36791111 PMCID: PMC9974408 DOI: 10.1073/pnas.2216367120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/12/2023] [Indexed: 02/16/2023] Open
Abstract
Recently, evidence for a conducting surface state (CSS) below 19 K was reported for the correlated d-electron small gap semiconductor FeSi. In the work reported herein, the CSS and the bulk phase of FeSi were probed via electrical resistivity ρ measurements as a function of temperature T, magnetic field B to 60 T, and pressure P to 7.6 GPa, and by means of a magnetic field-modulated microwave spectroscopy (MFMMS) technique. The properties of FeSi were also compared with those of the Kondo insulator SmB6 to address the question of whether FeSi is a d-electron analogue of an f-electron Kondo insulator and, in addition, a "topological Kondo insulator" (TKI). The overall behavior of the magnetoresistance of FeSi at temperatures above and below the onset temperature TS = 19 K of the CSS is similar to that of SmB6. The two energy gaps, inferred from the ρ(T) data in the semiconducting regime, increase with pressure up to about 7 GPa, followed by a drop which coincides with a sharp suppression of TS. Several studies of ρ(T) under pressure on SmB6 reveal behavior similar to that of FeSi in which the two energy gaps vanish at a critical pressure near the pressure at which TS vanishes, although the energy gaps in SmB6 initially decrease with pressure, whereas in FeSi they increase with pressure. The MFMMS measurements showed a sharp feature at TS ≈ 19 K for FeSi, which could be due to ferromagnetic ordering of the CSS. However, no such feature was observed at TS ≈ 4.5 K for SmB6.
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Affiliation(s)
| | - Yuhang Deng
- Department of Physics, University of CaliforniaSan Diego, La Jolla, CA92093
| | - Camilla M. Moir
- Department of Physics, University of CaliforniaSan Diego, La Jolla, CA92093
| | - Yuankan Fang
- Department of Physics, University of CaliforniaSan Diego, La Jolla, CA92093
| | - Sheng Ran
- Department of Physics, University of CaliforniaSan Diego, La Jolla, CA92093
| | - Hongbo Lou
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai201203, People’s Republic of China
| | - Shubin Li
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai201203, People’s Republic of China
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, Villeurbanne69100, France
| | - Qiaoshi Zeng
- Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai201203, People’s Republic of China
| | - Lei Shu
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai200433, People’s Republic of China
- Shanghai Research Center for Quantum Sciences, Shanghai201315, People’s Republic of China
| | | | - Ivan K. Schuller
- Department of Physics, University of CaliforniaSan Diego, La Jolla, CA92093
| | | | - Zachary Fisk
- University of California Irvine, Irvine, CA92967
| | | | - M. Brian Maple
- Department of Physics, University of CaliforniaSan Diego, La Jolla, CA92093
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Mulder L, van de Glind H, Brinkman A, Concepción O. Enhancement of the Surface Morphology of (Bi 0.4Sb 0.6) 2Te 3 Thin Films by In Situ Thermal Annealing. Nanomaterials (Basel) 2023; 13:763. [PMID: 36839131 PMCID: PMC9961334 DOI: 10.3390/nano13040763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 06/18/2023]
Abstract
The study of the exotic properties of the surface states of topological insulators requires defect-free and smooth surfaces. This work aims to study the enhancement of the surface morphology of optimally doped, high-crystalline (Bi0.4Sb0.6)2Te3 films deposited by molecular beam epitaxy on Al2O3 (001) substrates. Atomic force microscopy shows that by employing an in situ thermal post anneal, the surface roughness is reduced significantly, and transmission electron microscopy reveals that structural defects are diminished substantially. Thence, these films provide a great platform for the research on the thickness-dependent properties of topological insulators.
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Affiliation(s)
- Liesbeth Mulder
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Hanne van de Glind
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Omar Concepción
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
- Peter Grünberg Institute (PGI-9), Forschungszentrum Juelich, 52425 Juelich, Germany
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41
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Wang Y, Bobev S. Synthesis and Crystal Structure of the Zintl Phases NaSrSb, NaBaSb and NaEuSb. Materials (Basel) 2023; 16:1428. [PMID: 36837056 PMCID: PMC9959472 DOI: 10.3390/ma16041428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
This work details the synthesis and the crystal structures of the ternary compounds NaSrSb, NaBaSb and NaEuSb. They are isostructural and adopt the hexagonal ZrNiAl-type structure (space group P6¯2m; Pearson code hP9). The structure determination in all three cases was performed using single-crystal X-ray diffraction methods. The structure features isolated Sb3- anions arranged in layers stacked along the crystallographic c-axis. In the interstices, alkali and alkaline-earth metal cations are found in tetrahedral and square pyramidal coordination environments, respectively. The formal partitioning of the valence electrons adheres to the valence rules, i.e., Na+Sr2+Sb3-, Na+Ba2+Sb3- and Na+Eu2+Sb3- can be considered as Zintl phases with intrinsic semiconductor behavior. Electronic band structure calculations conducted for NaBaSb are consistent with this notion and show a direct gap of approx. 0.9 eV. Additionally, the calculations hint at possible inverted Dirac cones, a feature that is reminiscent of topological quantum materials.
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42
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Tay H, Zhao YF, Zhou LJ, Zhang R, Yan ZJ, Zhuo D, Chan MHW, Chang CZ. Environmental Doping-Induced Degradation of the Quantum Anomalous Hall Insulators. Nano Lett 2023; 23:1093-1099. [PMID: 36715442 DOI: 10.1021/acs.nanolett.2c04871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The quantum anomalous Hall (QAH) insulator carries dissipation-free chiral edge current and thus provides a unique opportunity to develop energy-efficient transformative information technology. Despite promising advances, the QAH insulator has thus far eluded any practical applications. In addition to its low working temperature, the QAH state in magnetically doped topological insulators usually deteriorates with time in ambient conditions. In this work, we store three QAH devices with similar initial properties in different environments. The QAH device without a protection layer in air shows clear degradation and becomes hole-doped. The QAH device kept in an argon glovebox without a protection layer shows no measurable degradation after 560 h, and the device protected by a 3 nm AlOx protection layer in air shows minimal degradation with stable QAH properties. Our work shows a route to preserve the dissipation-free chiral edge state in QAH devices for potential applications in quantum information technology.
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Affiliation(s)
- Han Tay
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Yi-Fan Zhao
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ling-Jie Zhou
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ruoxi Zhang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Zi-Jie Yan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Deyi Zhuo
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Moses H W Chan
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Cui-Zu Chang
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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43
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Ruckhofer A, Benedek G, Bremholm M, Ernst WE, Tamtögl A. Observation of Dirac Charge-Density Waves in Bi 2Te 2Se. Nanomaterials (Basel) 2023; 13:476. [PMID: 36770437 PMCID: PMC9919891 DOI: 10.3390/nano13030476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 06/18/2023]
Abstract
While parallel segments in the Fermi level contours, often found at the surfaces of topological insulators (TIs), would imply "strong" nesting conditions, the existence of charge-density waves (CDWs)-periodic modulations of the electron density-has not been verified up to now. Here, we report the observation of a CDW at the surface of the TI Bi2Te2Se(111), below ≈350K, by helium-atom scattering and, thus, experimental evidence for a CDW involving Dirac topological electrons. Deviations of the order parameter observed below 180K, and a low-temperature break of time reversal symmetry, suggest the onset of a spin-density wave with the same period as the CDW in the presence of a prominent electron-phonon interaction, originating from Rashba spin-orbit coupling.
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Affiliation(s)
- Adrian Ruckhofer
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Giorgio Benedek
- Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
- Donostia International Physics Center, University of the Basque Country, Paseo M. de Lardizabal 4, 20018 Donostia/San Sebastián, Spain
| | - Martin Bremholm
- Centre for Materials Crystallography, Department of Chemistry and iNANO, Aarhus University, 8000 Aarhus, Denmark
| | - Wolfgang E. Ernst
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
| | - Anton Tamtögl
- Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
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Kölzer J, Jalil AR, Rosenbach D, Arndt L, Mussler G, Schüffelgen P, Grützmacher D, Lüth H, Schäpers T. Supercurrent in Bi 4Te 3 Topological Material-Based Three-Terminal Junctions. Nanomaterials (Basel) 2023; 13:293. [PMID: 36678045 PMCID: PMC9867302 DOI: 10.3390/nano13020293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
In this paper, in an in situ prepared three-terminal Josephson junction based on the topological insulator Bi4Te3 and the superconductor Nb the transport properties are studied. The differential resistance maps as a function of two bias currents reveal extended areas of Josephson supercurrent, including coupling effects between adjacent superconducting electrodes. The observed dynamics for the coupling of the junctions is interpreted using a numerical simulation of a similar geometry based on a resistively and capacitively shunted Josephson junction model. The temperature dependency indicates that the device behaves similar to prior experiments with single Josephson junctions comprising topological insulators' weak links. Irradiating radio frequencies to the junction, we find a spectrum of integer Shapiro steps and an additional fractional step, which is interpreted with a skewed current-phase relationship. In a perpendicular magnetic field, we observe Fraunhofer-like interference patterns in the switching currents.
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Affiliation(s)
- Jonas Kölzer
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Abdur Rehman Jalil
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Daniel Rosenbach
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Lisa Arndt
- JARA Institute for Quantum Information, RWTH Aachen University, 52056 Aachen, Germany
| | - Gregor Mussler
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Peter Schüffelgen
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Detlev Grützmacher
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Hans Lüth
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
| | - Thomas Schäpers
- Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- JARA-Fundamentals of Future Information Technology, Jülich-Aachen Research Alliance, Forschungszentrum Jülich and RWTH Aachen University, 52425 Jülich, Germany
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45
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Halder D, Ganguly S, Basu S. Properties of the non-Hermitian SSH model: role ofPTsymmetry. J Phys Condens Matter 2022; 35:105901. [PMID: 36542860 DOI: 10.1088/1361-648x/acadc5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
The present work addresses the distinction between the topological properties ofPTsymmetric and non-PTsymmetric scenarios for the non-Hermitian Su-Schrieffer-Heeger model. The non-PTsymmetric case is represented by non-reciprocity in both the inter- and the intra-cell hopping amplitudes, while the one withPTsymmetry is modeled by a complex on-site staggered potential. In particular, we study the loci of the exceptional points, the winding numbers, band structures, and explore the breakdown of bulk-boundary correspondence (BBC). We further study the interplay of the dimerization strengths on the observables for these cases. The non-PTsymmetric case denotes a more familiar situation, where the winding number abruptly changes by half-integer through tuning of the non-reciprocity parameters, and demonstrates a complete breakdown of BBC, thereby showing non-Hermitian skin effect. The topological nature of thePTsymmetric case appears to follow closely to its Hermitian analogue, except that it shows unbroken (broken) regions with complex (purely real) energy spectra, while another variant of the winding number exhibits a continuous behavior as a function of the strength of the potential, while the conventional BBC is preserved.
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Affiliation(s)
- Dipendu Halder
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Sudin Ganguly
- Department of Physics, School of Applied Sciences, University of Science and Technology Meghalaya, Ri-Bhoi 793101, India
| | - Saurabh Basu
- Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
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Vyazovskaya AY, Petrov EK, Koroteev YM, Bosnar M, Silkin IV, Chulkov EV, Otrokov MM. Superlattices of Gadolinium and Bismuth Based Thallium Dichalcogenides as Potential Magnetic Topological Insulators. Nanomaterials (Basel) 2022; 13:38. [PMID: 36615948 PMCID: PMC9824305 DOI: 10.3390/nano13010038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/17/2022] [Accepted: 12/17/2022] [Indexed: 06/17/2023]
Abstract
Using relativistic spin-polarized density functional theory calculations we investigate magnetism, electronic structure and topology of the ternary thallium gadolinium dichalcogenides TlGdZ2 (Z= Se and Te) as well as superlattices on their basis. We find TlGdZ2 to have an antiferromagnetic exchange coupling both within and between the Gd layers, which leads to frustration and a complex magnetic structure. The electronic structure calculations reveal both TlGdSe2 and TlGdTe2 to be topologically trivial semiconductors. However, as we show further, a three-dimensional (3D) magnetic topological insulator (TI) state can potentially be achieved by constructing superlattices of the TlGdZ2/(TlBiZ2)n type, in which structural units of TlGdZ2 are alternated with those of the isomorphic TlBiZ2 compounds, known to be non-magnetic 3D TIs. Our results suggest a new approach for achieving 3D magnetic TI phases in such superlattices which is applicable to a large family of thallium rare-earth dichalcogenides and is expected to yield a fertile and tunable playground for exotic topological physics.
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Affiliation(s)
- Alexandra Yu. Vyazovskaya
- Laboratory of Nanostructured Surfaces and Coatings, Tomsk State University, Tomsk 634050, Russia
- Laboratory of Electronic and Spin Structure of Nanosystems, St. Petersburg State University, St. Petersburg 198504, Russia
| | - Evgeniy K. Petrov
- Laboratory of Nanostructured Surfaces and Coatings, Tomsk State University, Tomsk 634050, Russia
- Laboratory of Electronic and Spin Structure of Nanosystems, St. Petersburg State University, St. Petersburg 198504, Russia
| | - Yury M. Koroteev
- Laboratory of Electronic and Spin Structure of Nanosystems, St. Petersburg State University, St. Petersburg 198504, Russia
- Institute of Strength Physics and Materials Science, Tomsk 634021, Russia
| | - Mihovil Bosnar
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080 Donostia-San Sebastián, Basque Country, Spain
| | - Igor V. Silkin
- Laboratory of Nanostructured Surfaces and Coatings, Tomsk State University, Tomsk 634050, Russia
| | - Evgueni V. Chulkov
- Laboratory of Electronic and Spin Structure of Nanosystems, St. Petersburg State University, St. Petersburg 198504, Russia
- Donostia International Physics Center (DIPC), 20018 Donostia-San Sebastián, Basque Country, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, 20080 Donostia-San Sebastián, Basque Country, Spain
| | - Mikhail M. Otrokov
- Centro de Física de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, 20018 Donostia-San Sebastián, Basque Country, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Basque Country, Spain
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47
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Zhou Y, Chen MN. Surface plasmons in anisotropic 3D gapped topological insulators. J Phys Condens Matter 2022; 35:085001. [PMID: 36541525 DOI: 10.1088/1361-648x/aca7aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Topological insulators (TIs) are materials having conductive surfaces but insulating bulk, which are ideal platforms for plasmonic applications. The most commonly known TIs, such as Bi2Se3and Bi2Te3, are in fact highly anisotropic. The dielectric constants are largely different parallel and perpendicular to the surface. Here, we have extended the electromagnetic calculations of the surface plasmons in TIs to the anisotropic case. Magnetic field perpendicular to the surface is allowed, which opens a gap among the surface states. We model anisotropic TIs as bulk dielectric materials with different in-plane and out-of-plane permittivities; the surface states caused by the band inversion lead to a two-dimensional conductivity which supports surface plasmons. We have found two rather than one surface modes. Due to such anisotropy, quasi transverse electric (TE) polarized mode may occur near the interband transition threshold. Far below the transition frequency, another mode with both TE and transverse magnetic polarized components dominates, the dispersion relation of which is seriously modified by the Hall conductivity. By taking Bi2Te3as an example, we have derived the conductivity tensor with the consideration of the hexagonal warping effect, and solved the above mentioned two surface plasmon modes. In the end, finite element method has been used to calculate the electric field distributions. Our extension of the electromagnetic calculations of surface plasmons including a specific kind of anisotropy might be useful in other surface conductive materials with similar symmetry as well.
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Affiliation(s)
- Yu Zhou
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
| | - M N Chen
- School of Science, Hangzhou Dianzi University, Hangzhou 310018, People's Republic of China
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48
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Llacsahuanga Allcca AE, Pan XC, Miotkowski I, Tanigaki K, Chen YP. Gate-Tunable Anomalous Hall Effect in Stacked van der Waals Ferromagnetic Insulator- Topological Insulator Heterostructures. Nano Lett 2022; 22:8130-8136. [PMID: 36215229 DOI: 10.1021/acs.nanolett.2c02571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The search of novel topological states, such as the quantum anomalous Hall insulator and chiral Majorana fermions, has motivated different schemes to introduce magnetism into topological insulators. A promising scheme is using the magnetic proximity effect (MPE), where a ferromagnetic insulator magnetizes the topological insulator. Most of these heterostructures are synthesized by growth techniques which prevent mixing many of the available ferromagnetic and topological insulators due to difference in growth conditions. Here, we demonstrate that MPE can be obtained in heterostructures stacked via the dry transfer of flakes of van der Waals ferromagnetic and topological insulators (Cr2Ge2Te6/BiSbTeSe2), as evidenced in the observation of an anomalous Hall effect (AHE). Furthermore, devices made from these heterostructures allow modulation of the AHE when controlling the carrier density via electrostatic gating. These results show that simple mechanical transfer of magnetic van der Waals materials provides another possible avenue to magnetize topological insulators by MPE.
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Affiliation(s)
- Andres E Llacsahuanga Allcca
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Quantum Science and Engineering Institute and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Xing-Chen Pan
- WPI Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
| | - Ireneusz Miotkowski
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Katsumi Tanigaki
- WPI Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Yong P Chen
- Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Quantum Science and Engineering Institute and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, United States
- WPI Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Institute of Physics and Astronomy and Villum Center for Hybrid Quantum Materials and Devices, Aarhus University, 8000 Aarhus-C, Denmark
- Center for Science and Innovation in Spintronics, Tohoku University, Sendai 980-8577, Japan
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Yu R, Cao JF, Meng XY, Zhu FY, Li JQ, Qu GX, Huang YB, Wang Y, Tai RZ. Highly Tunable Charge-Spin Conversion in Topological Insulator Cr 0.08-(Bi 0.37Sb 0.63) 1.92Te 3 via Ferroelectric Polarization. ACS Appl Mater Interfaces 2022; 14:48171-48178. [PMID: 36251523 DOI: 10.1021/acsami.2c09778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Topological insulators possess strong spin-orbit coupling, which potentially presents efficient charge-spin interconversion. The effective manipulation of this conversion plays a central role in spin-based device applications and is attracting increasing attention nowadays. In this study, by constructing a multifunctional hybrid device Cr-BST/Py/PMN-PT and applying spin-torque ferromagnetic resonance measurement, continuously controllable charge-spin conversion efficiency and even the enhancement of its value up to about 450% are realized via regulation of the ferroelectric polarization in the topological insulator Cr-BST. The band structure of Cr-BST characterized by angle-resolved photoelectron spectroscopy measurement presents an apparent Dirac-like state located at the large band gap of the bulk state near the Fermi level, which indicates a surface state-dominated contribution to the charge-spin conversion. Further investigation via density functional theory on the electronic structure of BST verifies that the controllable conversion efficiency dominantly originates from the evolution of the band structure under strain modulation. These findings demonstrate TIs as one of the promising materials for the charge-spin interconversion and its regulation, which are instructive for low-dissipation spintronics devices.
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Affiliation(s)
- Rui Yu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Jie Feng Cao
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Xiang Yu Meng
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Fang Yuan Zhu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Jun Qin Li
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Ge Xing Qu
- Institute of Physics, Chinese Academy of Sciences, Beijing100190, China
| | - Yao Bo Huang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Yong Wang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
| | - Ren Zhong Tai
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai201204, China
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Kuznetsov KA, Tarasenko SA, Kovaleva PM, Kuznetsov PI, Lavrukhin DV, Goncharov YG, Ezhov AA, Ponomarev DS, Kitaeva GK. Topological Insulator Films for Terahertz Photonics. Nanomaterials (Basel) 2022; 12:nano12213779. [PMID: 36364555 PMCID: PMC9658460 DOI: 10.3390/nano12213779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 10/14/2022] [Accepted: 10/24/2022] [Indexed: 05/15/2023]
Abstract
We discuss experimental and theoretical studies of the generation of the third terahertz (THz) frequency harmonic in thin films of Bi2Se3 and Bi2-xSbxTe3-ySey (BSTS) topological insulators (TIs) and the generation of THz radiation in photoconductive antennas based on the TI films. The experimental results, supported by the developed kinetic theory of third harmonic generation, show that the frequency conversion in TIs is highly efficient because of the linear energy spectrum of the surface carriers and fast energy dissipation. In particular, the dependence of the third harmonic field on the pump field remains cubic up to the pump fields of 100 kV/cm. The generation of THz radiation in TI-based antennas is obtained and described for the pump, with the energy of photons corresponding to the electron transitions to higher conduction bands. Our findings open up possibilities for advancing TI-based films into THz photonics as efficient THz wave generators and frequency converters.
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Affiliation(s)
- Kirill A. Kuznetsov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Correspondence:
| | | | - Polina M. Kovaleva
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Denis V. Lavrukhin
- Institute of Ultra High Frequency Semiconductor Electronics of RAS, 117105 Moscow, Russia
| | | | - Alexander A. Ezhov
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Dmitry S. Ponomarev
- Institute of Ultra High Frequency Semiconductor Electronics of RAS, 117105 Moscow, Russia
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Galiya Kh. Kitaeva
- Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia
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