1
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Zhang W, Zhang ZM, Nie JH, Gong BC, Cai M, Liu K, Lu ZY, Fu YS. Spin-Resolved Imaging of Antiferromagnetic Order in Fe 4 Se 5 Ultrathin Films on SrTiO 3. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209931. [PMID: 36790865 DOI: 10.1002/adma.202209931] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/17/2023] [Indexed: 05/12/2023]
Abstract
Unraveling the magnetic order in iron chalcogenides and pnictides at atomic scale is pivotal for understanding their unconventional superconducting pairing mechanism, but is experimentally challenging. Here, by utilizing spin-polarized scanning tunneling microscopy, real-space spin contrasts are successfully resolved to exhibit atomically unidirectional stripes in Fe4 Se5 ultrathin films, the plausible closely related compound of bulk FeSe with ordered Fe-vacancies, which are grown by molecular beam epitaxy. As is substantiated by the first-principles electronic structure calculations, the spin contrast originates from a pair-checkerboard antiferromagnetic ground state with in-plane magnetization, which is modulated by a spin-lattice coupling. These measurements further identify three types of nanoscale antiferromagnetic domains with distinguishable spin contrasts, which are subject to thermal fluctuations into short-ranged patches at elevated temperatures. This work provides promising opportunities in understanding the emergent magnetic order and the electronic phase diagram for FeSe-derived superconductors.
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Affiliation(s)
- Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhi-Mo Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jin-Hua Nie
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Ben-Chao Gong
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, 100872, China
| | - Min Cai
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Kai Liu
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, 100872, China
| | - Zhong-Yi Lu
- Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing, 100872, China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
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2
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Desai DC, Park J, Zhou JJ, Bernardi M. Dominant Two-Dimensional Electron-Phonon Interactions in the Bulk Dirac Semimetal Na 3Bi. NANO LETTERS 2023; 23:3947-3953. [PMID: 37092857 DOI: 10.1021/acs.nanolett.3c00713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Bulk Dirac semimetals (DSMs) exhibit unconventional transport properties and phase transitions due to their peculiar low-energy band structure, yet the electronic interactions governing nonequilibrium phenomena in DSMs are not fully understood. Here we show that electron-phonon (e-ph) interactions in a prototypical bulk DSM, Na3Bi, are predominantly two-dimensional (2D). Our first-principles calculations reveal a 2D optical phonon with strong e-ph interactions associated with in-plane vibrations of Na atoms. We show that this 2D mode governs e-ph scattering and charge transport in Na3Bi and induces a dynamical phase transition to a Weyl semimetal. Our work advances the quantitative analysis of electron interactions in Na3Bi and reveals a dominant low-dimensional interaction in a bulk Dirac semimetal.
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Affiliation(s)
- Dhruv C Desai
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Jinsoo Park
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
| | - Jin-Jian Zhou
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Marco Bernardi
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, United States
- Department of Physics, California Institute of Technology, Pasadena, California 91125, United States
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3
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Zhang ZM, Gong BC, Nie JH, Meng F, Zhang Q, Gu L, Liu K, Lu ZY, Fu YS, Zhang W. Self-Intercalated 1T-FeSe 2 as an Effective Kagome Lattice. NANO LETTERS 2023; 23:954-961. [PMID: 36706049 DOI: 10.1021/acs.nanolett.2c04362] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
In kagome lattice, with the emergence of Dirac cones and flat band in electronic structure, it provides a versatile ground for exploring intriguing interplay among frustrated geometry, topology and correlation. However, such engaging interest is strongly limited by available kagome materials in nature. Here we report on a synthetic strategy of constructing kagome systems via self-intercalation of Fe atoms into the van der Waals gap of FeSe2 via molecular beam epitaxy. Using low-temperature scanning tunneling microscopy, we unveil a kagome-like morphology upon intercalating a 2 × 2 ordered Fe atoms, resulting in a stoichiometry of Fe5Se8. Both the bias-dependent STM imaging and theoretical modeling calculations suggest that the kagome pattern mainly originates from slight but important reconstruction of topmost Se atoms, incurred by the nonequivalent subsurface Fe sites due to the intercalation. Our study demonstrates an alternative approach of constructing artificial kagome structures, which envisions to be tuned for exploring correlated quantum states.
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Affiliation(s)
- Zhi-Mo Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan430074, China
| | - Ben-Chao Gong
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing100872, China
| | - Jin-Hua Nie
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan430074, China
| | - Fanqi Meng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, P.R. China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, P.R. China
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing100190, P.R. China
| | - Kai Liu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing100872, China
| | - Zhong-Yi Lu
- Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-nano Devices, Renmin University of China, Beijing100872, China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan430074, China
| | - Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan430074, China
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4
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Liang Y, Zheng F, Zhao P, Wang Q, Frauenheim T. Intrinsic Ferroelectric Quantum Spin Hall Insulator in Monolayer Na 3Bi with Surface Trimerization. J Phys Chem Lett 2022; 13:11059-11064. [PMID: 36416532 DOI: 10.1021/acs.jpclett.2c03270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Two-dimensional (2D) ferroelectric quantum spin Hall (FEQSH) insulator, which features coexisting ferroelectric and topologically insulating orders in two-dimension, is generally considered available only in engineered 2D systems. This is detrimental to the synthesis and application of next generation nonvolatile functional candidates. Therefore, exploring the intrinsic 2D FEQSH insulator is crucial. Here, by means of first-principles, we report a long-thought intrinsic 2D FEQSH insulator in monolayer Na3Bi with surface trimerization. The material harbors merits including large ferroelectric polarization, sizable nontrivial band gap, and low switching barrier, which are particularly beneficial for the detection and observation of ferroelectric topologically insulating states. Also, it is capable of nonvolatile switching of nontrivial spin textures via inherent ferroelectricity. The fantastic combination of excellent ferroelectric and topological phases in intrinsic the Na3Bi monolayer serves as an alluring platform for accelerating both scientific discoveries and innovative applications.
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Affiliation(s)
- Yan Liang
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100, People's Republic of China
| | - Fulu Zheng
- Bremen Center for Computational Materials Science, University of Bremen, Bremen, 28359, Germany
| | - Pei Zhao
- College of Physics and Optoelectronic Engineering, Faculty of Information Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100, People's Republic of China
| | - Qiang Wang
- Key laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University, Qinhuangdao, 066104, People's Republic of China
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen, Bremen, 28359, Germany
- Beijing Computational Science Research Center, Beijing, 100193, People's Republic of China
- Shenzhen JL Computational Science and Applied Research Institute, Shenzhen, 518109, People's Republic of China
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5
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Parfenov OE, Taldenkov AN, Averyanov DV, Sokolov IS, Kondratev OA, Borisov MM, Yakunin SN, Karateev IA, Tokmachev AM, Storchak VG. Layer-controlled evolution of electron state in the silicene intercalation compound SrSi 2. MATERIALS HORIZONS 2022; 9:2854-2862. [PMID: 36056695 DOI: 10.1039/d2mh00640e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Silicene, a Si-based analogue of graphene, holds a high promise for electronics because of its exceptional properties but a high chemical reactivity makes it a very challenging material to work with. The silicene lattice can be stabilized by active metals to form stoichiometric compounds MSi2. Being candidate topological semimetals, these materials provide an opportunity to probe layer dependence of unconventional electronic structures. It is demonstrated here that in the silicene compound SrSi2, the number of monolayers controls the electronic state. A series of films ranging from bulk-like multilayers down to a single monolayer have been synthesized on silicon and characterized with a combination of techniques - from electron and X-ray diffraction to high-resolution electron microscopy. Transport measurements reveal evolution of the chiral anomaly in bulk SrSi2 to weak localization in ultrathin films down to 3 monolayers followed by 3D and 2D strong localization in 2 and 1 monolayers, respectively. The results outline the range of stability of the chiral state, important for practical applications, and shed light on the localization phenomena in the limit of a few monolayers.
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Affiliation(s)
- Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Ivan S Sokolov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Oleg A Kondratev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Mikhail M Borisov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Sergey N Yakunin
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Igor A Karateev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow 123182, Russia.
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6
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Zhang Z, Nie J, Zhang Z, Yuan Y, Fu YS, Zhang W. Atomic Visualization and Switching of Ferroelectric Order in β-In 2 Se 3 Films at the Single Layer Limit. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106951. [PMID: 34755394 DOI: 10.1002/adma.202106951] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/24/2021] [Indexed: 06/13/2023]
Abstract
2D ferroelectrics have received wide interest due to the remarkable quantum states of emerging physics at reduced dimensionality, associated with their exotic properties in high-performance and nonvolatile functional devices. Here, by combing molecular beam epitaxy synthesis and scanning tunneling microscopy characterization, two metastable phases of layered In2 Se3 films: β'- and β*-In2 Se3 are reported, which develop different types of in-plane spontaneous polarizations, thus resulting in different striped morphologies. The anti-ferroelectric order in β'-In2 Se3 and ferroelectric order of β*-In2 Se3 are identified, respectively, down to the 2D limit by comprehensive investigations of structural and spectroscopic signatures, including the lattice distortion, the spatial profile of images, the formation of domain structure, and the electronic band-bending by polarization charges at edges. The ferroelectric switching between those two phases are further controlled via applying an electric field generated from the scanning tunneling microscopy tip in a reversible manner. The intriguing tunability between the (anti-)ferroelectric orders in the 2D limit provides a promising platform for studying the interplay between electronic structure and ferroelectricity in van der Waals materials, and promotes potential development of miniaturized transistors and memory devices based on electric polarizations.
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Affiliation(s)
- Zhimo Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jinhua Nie
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zhihao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yuan Yuan
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, China
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7
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Zhuang J, Li J, Liu Y, Mu D, Yang M, Liu Y, Zhou W, Hao W, Zhong J, Du Y. Epitaxial Growth of Quasi-One-Dimensional Bismuth-Halide Chains with Atomically Sharp Topological Non-Trivial Edge States. ACS NANO 2021; 15:14850-14857. [PMID: 34583466 DOI: 10.1021/acsnano.1c04928] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Quantum spin Hall insulators (QSHIs) have one-dimensional (1D) spin-momentum locked topological edge states (ES) inside the bulk band gap, which can serve as dissipationless channels for the practical applications in low consumption electronics and high performance spintronics. However, obtaining the clean and atomically sharp ES which serves as ideal 1D spin-polarized nondissipative conducting channels is demanding and still a challenge. Here, we report the formation of the quasi-1D Bi4I4 nanoribbons on the surface of Bi(111) with the support of the graphene-terminated 6H-SiC(0001) and the direct observation of the topological ES at the step edges by the scanning tunneling microscopy (STM) and spectroscopic-imaging results. The ES reside surround the edge of Bi4I4 nanoribbons and exhibits noteworthy robustness against nontime reversal symmetry (non-TRS) perturbations. The theoretical simulations verify the topological nontriviality of 1D ES, which is retained after considering the presence of the underlying Bi(111). Our study supports the existence of topological ES in Bi4I4 nanoribbons, benefiting to engineer the topological features by using the 1D nanoribbons as building blocks.
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Affiliation(s)
- Jincheng Zhuang
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Jin Li
- 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
| | - Dan Mu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Ming Yang
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Yani Liu
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
| | - Wei Zhou
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu 215500, China
| | - Weichang Hao
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Jianxin Zhong
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yi Du
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
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8
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Zhang Z, Yuan Y, Zhou W, Chen C, Yuan S, Zeng H, Fu YS, Zhang W. Strain-Induced Bandgap Enhancement of InSe Ultrathin Films with Self-Formed Two-Dimensional Electron Gas. ACS NANO 2021; 15:10700-10709. [PMID: 34080842 DOI: 10.1021/acsnano.1c03724] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomically thin indium selenide (InSe) is a representative two-dimensional (2D) family that have recently attracted extensive interest for their intriguing emerging physics and potential optoelectronic applications with high-performance. Here, by utilizing molecular beam epitaxy and scanning tunneling microscopy, we report a controlled synthesis of InSe thin films down to the monolayer limit and characterization of their electronic properties at atomic scale. Highly versatile growth conditions are developed to fabricate well crystalline InSe films, with a reversible and controllable phase transformation between InSe and In2Se3. The band gap size of InSe films, as enhanced by quantum confinement, increases with decreasing film thickness. Near various categories of lattice imperfections, the band gap becomes significantly enlarged, resulting in a type-I band alignments for lateral heterojunctions. Such band gap enhancement, as unveiled from our first-principles calculations, is ascribed to the local compressive strain imposed by the lattice imperfections. Moreover, InSe films host highly conductive 2D electron gas, manifesting prominent quasiparticle scattering signatures. The 2D electron gas is self-formed via substrate doping of electrons, which shift the Fermi level above the confinement-quantized conduction band. Our study identifies InSe ultrathin film as an appealing system for both fundamental research and potential applications in nanoelectrics and optoelectronics.
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Affiliation(s)
- Zhimo Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yuan Yuan
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Weiqing Zhou
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Chen Chen
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shengjun Yuan
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Hualing Zeng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Science at the Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
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9
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Zhou F, Liu Y, Kuang M, Wang P, Wang J, Yang T, Wang X, Cheng Z, Zhang G. Time-reversal-breaking Weyl nodal lines in two-dimensional A 3C 2 (A = Ti, Zr, and Hf) intrinsically ferromagnetic materials with high Curie temperature. NANOSCALE 2021; 13:8235-8241. [PMID: 33885113 DOI: 10.1039/d1nr00139f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Most materials that feature nontrivial band topology are spin-degenerate and three dimensional, strongly restricting them from application in spintronic nanodevices. Hence, two-dimensional (2D) intrinsically spin-polarized systems with rich topological elements are still in extreme scarcity. Here, 2D A3C2 (A = Ti, Zr, and Hf) materials with the P6[combining macron]m2 type structure are reported as new ferromagnetic materials with intrinsic magnetism and good stability. Unlike the Weyl nodal lines existing in nonmagnetic 2D systems, A3C2 hosts time-reversal-breaking Weyl nodal rings (two Γ-centered, one K-centered, and one K'-centered) without spin-orbit coupling (SOC). These nodal rings still remained under SOC with magnetization along the z direction (easy magnetization axis). More interestingly, the Curie temperatures (TC) of A3C2 were determined based on the Monte Carlo simulation. Ti3C2 features an extraordinary TC (above 800 K), and those of Zr3C2 and Hf3C2 are above room temperature. Therefore, A3C2 materials are excellent platforms to study magnetic Weyl nodal lines in high TC ferromagnetic 2D materials.
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Affiliation(s)
- Feng Zhou
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
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10
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Di Bernardo I, Hellerstedt J, Liu C, Akhgar G, Wu W, Yang SA, Culcer D, Mo SK, Adam S, Edmonds MT, Fuhrer MS. Progress in Epitaxial Thin-Film Na 3 Bi as a Topological Electronic Material. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2005897. [PMID: 33538071 DOI: 10.1002/adma.202005897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/24/2020] [Indexed: 06/12/2023]
Abstract
Trisodium bismuthide (Na3 Bi) is the first experimentally verified topological Dirac semimetal, and is a 3D analogue of graphene hosting relativistic Dirac fermions. Its unconventional momentum-energy relationship is interesting from a fundamental perspective, yielding exciting physical properties such as chiral charge carriers, the chiral anomaly, and weak anti-localization. It also shows promise for realizing topological electronic devices such as topological transistors. Herein, an overview of the substantial progress achieved in the last few years on Na3 Bi is presented, with a focus on technologically relevant large-area thin films synthesized via molecular beam epitaxy. Key theoretical aspects underpinning the unique electronic properties of Na3 Bi are introduced. Next, the growth process on different substrates is reviewed. Spectroscopic and microscopic features are illustrated, and an analysis of semiclassical and quantum transport phenomena in different doping regimes is provided. The emergent properties arising from confinement in two dimensions, including thickness-dependent and electric-field-driven topological phase transitions, are addressed, with an outlook toward current challenges and expected future progress.
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Affiliation(s)
- Iolanda Di Bernardo
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
| | - Jack Hellerstedt
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
| | - Chang Liu
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
| | - Golrokh Akhgar
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
| | - Weikang Wu
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Dimitrie Culcer
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, University of New South Wales, Sydney, New South Wales, 2052, Australia
- School of Physics, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Shaffique Adam
- Yale-NUS College, 16 College Ave West, Singapore, 138527, Singapore
| | - Mark T Edmonds
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, Victoria, 3800, Australia
| | - Michael S Fuhrer
- Australian Research Council Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Clayton, Victoria, 3800, Australia
- School of Physics and Astronomy, Monash University, Clayton, Victoria, 3800, Australia
- Monash Centre for Atomically Thin Materials, Monash University, Clayton, Victoria, 3800, Australia
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11
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Guo X, Yu R, Jiang J, Ma Z, Zhang X. Two-dimensional topological insulators exfoliated from Na 3Bi-like Dirac semimetals. Phys Chem Chem Phys 2021; 23:10545-10550. [PMID: 33900337 DOI: 10.1039/d1cp00736j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Topological insulation is widely predicted in two-dimensional (2D) materials realized by epitaxial growth or van der Waals (vdW) exfoliation. Such 2D topological insulators (TI's) host many interesting physical properties such as the quantum spin Hall effect and superconductivity. Here, we extend the search of 2D TI's into the exfoliatable non-vdW 2D crystals. We find that three-dimensional Dirac semimetals A3Bi (A = Na, K, Rb) (P3[combining macron]c1) can be exfoliated into 2D materials with exfoliation energies of 0.479-0.990 J m-2. Our careful examination of the topological invariants of exfoliated A3Bi monolayers/multilayers by using two well-established approaches reveals that bilayer and tetralayer Na3Bi are 2D TI's. It is found that the band gap of 2D TI's can be significantly increased by external strain. We further find that the predicted 2D TI's possess interesting hidden Rashba-like spin textures. Our results suggest a new arena to search for two-dimensional topological insulators and spintronic materials.
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Affiliation(s)
- Xiaoqiu Guo
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Ruixin Yu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Jingwen Jiang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Zhuang Ma
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Xiuwen Zhang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
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