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Zhang X, Li Y, Lu Q, Xiang X, Sun X, Tang C, Mahdi M, Conner C, Cook J, Xiong Y, Inman J, Jin W, Liu C, Cai P, Santos EJG, Phatak C, Zhang W, Gao N, Niu W, Bian G, Li P, Yu D, Long S. Epitaxial Growth of Large-Scale 2D CrTe 2 Films on Amorphous Silicon Wafers With Low Thermal Budget. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2311591. [PMID: 38426690 DOI: 10.1002/adma.202311591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/27/2024] [Indexed: 03/02/2024]
Abstract
2D van der Waals (vdW) magnets open landmark horizons in the development of innovative spintronic device architectures. However, their fabrication with large scale poses challenges due to high synthesis temperatures (>500 °C) and difficulties in integrating them with standard complementary metal-oxide semiconductor (CMOS) technology on amorphous substrates such as silicon oxide (SiO2) and silicon nitride (SiNx). Here, a seeded growth technique for crystallizing CrTe2 films on amorphous SiNx/Si and SiO2/Si substrates with a low thermal budget is presented. This fabrication process optimizes large-scale, granular atomic layers on amorphous substrates, yielding a substantial coercivity of 11.5 kilo-oersted, attributed to weak intergranular exchange coupling. Field-driven Néel-type stripe domain dynamics explain the amplified coercivity. Moreover, the granular CrTe2 devices on Si wafers display significantly enhanced magnetoresistance, more than doubling that of single-crystalline counterparts. Current-assisted magnetization switching, enabled by a substantial spin-orbit torque with a large spin Hall angle (85) and spin Hall conductivity (1.02 × 107 ℏ/2e Ω⁻¹ m⁻¹), is also demonstrated. These observations underscore the proficiency in manipulating crystallinity within integrated 2D magnetic films on Si wafers, paving the way for large-scale batch manufacturing of practical magnetoelectronic and spintronic devices, heralding a new era of technological innovation.
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Affiliation(s)
- Xiaoqian Zhang
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
- Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China
| | - Yue Li
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Qiangsheng Lu
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
- Material Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Xueqiang Xiang
- School of Microelectronics, University of Science and Technology of China, Hefei, 230026, China
| | - Xiaozhen Sun
- School of Microelectronics, University of Science and Technology of China, Hefei, 230026, China
| | - Chunli Tang
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Muntasir Mahdi
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Clayton Conner
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Jacob Cook
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Yuzan Xiong
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jerad Inman
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Physics, Oakland University, Rochester, MI, 48309, USA
| | - Wencan Jin
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, 36849, USA
- Department of Physics, Auburn University, Auburn, AL, 36849, USA
| | - Chang Liu
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - PeiYu Cai
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
| | - Elton J G Santos
- Institute for Condensed Matter Physics and Complex Systems, School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3FD, UK
- Higgs Centre for Theoretical Physics, The University of Edinburgh, Edinburgh, EH9 3FD, UK
- Donostia International Physics Center (DIPC), Donostia-San Sebastián, 20018, Basque Country, Spain
| | - Charudatta Phatak
- Materials Science Division, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Wei Zhang
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Physics, Oakland University, Rochester, MI, 48309, USA
| | - Nan Gao
- School of Microelectronics, University of Science and Technology of China, Hefei, 230026, China
| | - Wei Niu
- School of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China
| | - Guang Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, 65211, USA
| | - Peng Li
- School of Microelectronics, University of Science and Technology of China, Hefei, 230026, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Shibing Long
- School of Microelectronics, University of Science and Technology of China, Hefei, 230026, China
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Kang Y, Tan Y, Zhang R, Xie X, Hua W. In-Situ Chemical Thinning and Surface Doping of Layered Bi 2Se 3. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3725. [PMID: 36364501 PMCID: PMC9658795 DOI: 10.3390/nano12213725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
As a promising topological insulator, two-dimensional (2D) bismuth selenide (Bi2Se3) attracts extensive research interest. Controllable surface doping of layered Bi2Se3 becomes a crucial issue for the relevant applications. Here, we propose an efficient method for the chemical thinning and surface doping of layered Bi2Se3, forming Se/Bi2Se3 heterostructures with tunable thickness ranging from a few nanometers to hundreds of nanometers. The thickness can be regulated by varying the reaction time and large-size few-layer Bi2Se3 sheets can be obtained. Different from previous liquid-exfoliation methods that require complex reaction process, in-situ and thickness-controllable exfoliation of large-size layered Bi2Se3 can be realized via the developed method. Additionally, the formation of Se nanomeshes coated on the Bi2Se3 sheets remarkably enhance the intensity of Raman vibration peaks, indicating that this method can be used for surface-enhanced Raman scattering. The proposed chemical thinning and surface-doping method is expected to be extended to other bulk-layered materials for high-efficient preparation of 2D heterostructures.
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Affiliation(s)
- Yan Kang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Yinlong Tan
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Renyan Zhang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
| | - Xiangnan Xie
- College of Computer Science and Technology, National University of Defense Technology, Changsha 410073, China
| | - Weihong Hua
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
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Huang SM, Wang PC, Chen PC. The Lattice Distortion-Induced Ferromagnetism in the Chemical-Bonded MoSe 2/WSe 2 at Room Temperature. NANOSCALE RESEARCH LETTERS 2022; 17:55. [PMID: 35622164 PMCID: PMC9142725 DOI: 10.1186/s11671-022-03692-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/13/2022] [Indexed: 06/15/2023]
Abstract
Ferromagnetism to non-ferromagnetism transition is detected in a chemically bonded MoSe[Formula: see text]/WSe[Formula: see text] powder with different thermal annealing temperatures. All samples exhibit ferromagnetism and Raman redshift, except for the 1100 °C thermally annealed sample in which the MoSe[Formula: see text] and WSe[Formula: see text] are thermally dissociated and geometrically separated. The element analysis reveals no significant element ratio difference and detectable magnetic elements in all samples. These results support that, in contrast to the widely reported structure defect or transition element dopant, the observed ferromagnetism originates from the structure distortion due to the chemical bonding at the interface between MoSe[Formula: see text] and WSe[Formula: see text].
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Affiliation(s)
- Shiu-Ming Huang
- Department of Physics, National Sun Yat-Sen University, 80424, Kaohsiung, Taiwan.
| | - Pin-Cing Wang
- Department of Physics, National Sun Yat-Sen University, 80424, Kaohsiung, Taiwan
| | - Pin-Cyuan Chen
- Department of Physics, National Sun Yat-Sen University, 80424, Kaohsiung, Taiwan
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Yao Y, Zhan X, Sendeku MG, Yu P, Dajan FT, Zhu C, Li N, Wang J, Wang F, Wang Z, He J. Recent progress on emergent two-dimensional magnets and heterostructures. NANOTECHNOLOGY 2021; 32:472001. [PMID: 34315143 DOI: 10.1088/1361-6528/ac17fd] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Intrinsic two-dimensional (2D) magnetic materials own strong long-range magnetism while their characteristics of the ultrathin thickness and smooth surface provide an ideal platform for manipulating the magnetic properties at 2D limit. This makes them to be potential candidates in various spintronic applications compared to their corresponding bulk counterparts. The discovery of magnetic ordering in 2D CrI3and Gr2Ge2Te6nanostructures stimulated tremendous research interest in both experimental and theoretical studies on various intrinsic magnets at 2D limit. This review gives a comprehensive overview of the recent progress on the emergent 2D magnets and heterostructures. Firstly, several kinds of typical 2D magnetic materials discovered in the last few years and their fabrication methods are summarized in detail. Secondly, the current strategies for manipulating magnetic properties in 2D materials are further discussed. Then, the recent advances on the construction of representative van der Waals magnetic heterostructures and their respective performance are provided. With the hope of motivating the researchers in this area, we finally offered the challenges and outlook on 2D magnetism.
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Affiliation(s)
- Yuyu Yao
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Sino-Danish Center for Education, Beijing 100049, People's Republic of China
| | - Xueying Zhan
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Marshet Getaye Sendeku
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Peng Yu
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Fekadu Tsegaye Dajan
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Chuanchao Zhu
- Institute for Quantum Information & State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073, People's Republic of China
| | - Ningning Li
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Sino-Danish Center for Education, Beijing 100049, People's Republic of China
| | - Junjun Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Feng Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Zhenxing Wang
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jun He
- CAS Center for Excellence in Nanoscience, CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
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5
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Yano R, Kudriashov A, Hirose HT, Tsuda T, Kashiwaya H, Sasagawa T, Golubov AA, Stolyarov VS, Kashiwaya S. Magnetic Gap of Fe-Doped BiSbTe 2Se Bulk Single Crystals Detected by Tunneling Spectroscopy and Gate-Controlled Transports. J Phys Chem Lett 2021; 12:4180-4186. [PMID: 33900082 DOI: 10.1021/acs.jpclett.1c00869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Topological insulators with broken time-reversal symmetry and the Fermi level within the magnetic gap at the Dirac cone provides exotic topological magneto-electronic phenomena. Here, we introduce an improved magnetically doped topological insulator, Fe-doped BiSbTe2Se (Fe-BSTS) bulk single crystal, with an ideal Fermi level. Scanning tunneling microscopy and spectroscopy (STM/STS) measurements revealed that the surface state possesses a Dirac cone with the Dirac point just below the Fermi level by 12 meV. The normalized dI/dV spectra suggest a gap opening with Δmag ∼55 meV, resulting in the Fermi level within the opened gap. Ionic-liquid gated-transport measurements also support the Dirac point just below the Fermi level and the presence of the magnetic gap. The chemical potential of the surface state can be fully tuned by ionic-liquid gating, and thus the Fe-doped BSTS provides an ideal platform to investigate exotic quantum topological phenomena.
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Affiliation(s)
- Rikizo Yano
- Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya 464-8603, Japan
- Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Andrei Kudriashov
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Oblast 141700, Russia
| | - Hishiro T Hirose
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Taiki Tsuda
- Applied Physics, Nagoya University, Nagoya 464-8603, Japan
| | - Hiromi Kashiwaya
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan
| | - Takao Sasagawa
- Laboratory for Materials and Structures, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Alexander A Golubov
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Oblast 141700, Russia
- Faculty of Science and Technology and MESA+ Institute of Nanotechnology, Enschede 7500 AE, The Netherlands
| | - Vasily S Stolyarov
- TQPSS Lab, Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Oblast 141700, Russia
- Dukhov Research Institute of Automatics (VNIIA), Moscow 127055, Russia
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Room-temperature intrinsic ferromagnetism in epitaxial CrTe 2 ultrathin films. Nat Commun 2021; 12:2492. [PMID: 33941773 PMCID: PMC8093203 DOI: 10.1038/s41467-021-22777-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 03/22/2021] [Indexed: 11/08/2022] Open
Abstract
While the discovery of two-dimensional (2D) magnets opens the door for fundamental physics and next-generation spintronics, it is technically challenging to achieve the room-temperature ferromagnetic (FM) order in a way compatible with potential device applications. Here, we report the growth and properties of single- and few-layer CrTe2, a van der Waals (vdW) material, on bilayer graphene by molecular beam epitaxy (MBE). Intrinsic ferromagnetism with a Curie temperature (TC) up to 300 K, an atomic magnetic moment of ~0.21 [Formula: see text]/Cr and perpendicular magnetic anisotropy (PMA) constant (Ku) of 4.89 × 105 erg/cm3 at room temperature in these few-monolayer films have been unambiguously evidenced by superconducting quantum interference device and X-ray magnetic circular dichroism. This intrinsic ferromagnetism has also been identified by the splitting of majority and minority band dispersions with ~0.2 eV at Г point using angle-resolved photoemission spectroscopy. The FM order is preserved with the film thickness down to a monolayer (TC ~ 200 K), benefiting from the strong PMA and weak interlayer coupling. The successful MBE growth of 2D FM CrTe2 films with room-temperature ferromagnetism opens a new avenue for developing large-scale 2D magnet-based spintronics devices.
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7
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Figueroa AI, Bonell F, Cuxart MG, Valvidares M, Gargiani P, van der Laan G, Mugarza A, Valenzuela SO. Absence of Magnetic Proximity Effect at the Interface of Bi_{2}Se_{3} and (Bi,Sb)_{2}Te_{3} with EuS. PHYSICAL REVIEW LETTERS 2020; 125:226801. [PMID: 33315425 DOI: 10.1103/physrevlett.125.226801] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 09/02/2020] [Accepted: 10/16/2020] [Indexed: 06/12/2023]
Abstract
We performed x-ray magnetic circular dichroism (XMCD) measurements on heterostructures comprising topological insulators (TIs) of the (Bi,Sb)_{2}(Se,Te)_{3} family and the magnetic insulator EuS. XMCD measurements allow us to investigate element-selective magnetic proximity effects at the very TI/EuS interface. A systematic analysis reveals that there is neither significant induced magnetism within the TI nor an enhancement of the Eu magnetic moment at such interface. The induced magnetic moments in Bi, Sb, Te, and Se sites are lower than the estimated detection limit of the XMCD measurements of ∼10^{-3} μ_{B}/at.
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Affiliation(s)
- A I Figueroa
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - F Bonell
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - M G Cuxart
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Universitat Autònoma de Barcelona (UAB), Bellaterra 08193, Spain
| | - M Valvidares
- ALBA Synchrotron Light Source, Barcelona 08290, Spain
| | - P Gargiani
- ALBA Synchrotron Light Source, Barcelona 08290, Spain
| | - G van der Laan
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - A Mugarza
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
| | - S O Valenzuela
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain
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Shieh M, Liu YH, Huang CY, Chen SW, Cheng WK, Chien LT. The First Naked Bismuth-Chalcogen Metal Carbonyl Clusters: Extraordinary Nucleophilicity of the Bi Atom and Semiconducting Characteristics. Inorg Chem 2019; 58:6706-6721. [PMID: 30933492 DOI: 10.1021/acs.inorgchem.9b00080] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mixed bismuth-chalcogen-iron clusters [{EFe3(CO)9}Bi]- [E = Te (1a) or Se (1b)] were produced via the reduction of BiCl3 with [EFe3(CO)9]2- under mild conditions. X-ray analysis showed that both clusters 1a and 1b had a square-pyramidal geometry, where the naked Bi and chalcogen both adopted a distorted trigonal-pyramidal configuration with a stereoactive lone pair. Complexes 1a and 1b can be further functionalized by methylation and metalation, which permits the nucleophilicity of the 6s/5s and 6s/4s lone pairs to be compared. In the metalation, the 6s pair of the Bi atom in 1a and 1b had an extraordinary nucleophilicity toward the unsaturated Cr(CO)5 fragment, even in the presence of the more chemically active 5s or 4s pair, whereas in the case of methylation, only the 4s pair of Se could be selectively alkylated. Upon oxidation of 1a and 1b with suitable oxidizing agents, NaBiO3 or K2SeO3, Bi-E bonded tetrahedral complexes [{EFe2(CO)6}Bi]- [E = Te (4a) or Se (4b)] were formed by the elimination of one Fe(CO)3 vertex. X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, and density functional theory (DFT) calculations showed that all of the Bi atoms in these complexes had oxidation states close to +1. Due to the electropositive character of the Bi atom, pronounced induced Bi···E inter- and intramolecular interactions were evident in 1a (1b), 4a (4b), and the metalated 3a (3b), where their linear-like ···Bi···E··· or zigzag-like ···Bi-E··· (E = Te or Se) chain or the Bi···E···E···Bi (E = Te or Se) dimeric chain can further expand into the two-dimensional network via nonclassical C-H···O(carbonyl) interactions, supported by noncovalent interaction index and DFT calculations. These positively charged Bi-induced Bi···E (E = Te or Se) and carbonyl-aided weak interactions can facilitate efficient electron transport within these ternary Bi-E-Fe or quaternary Bi-E-Fe-Cr cluster-based frameworks, resulting in semiconducting behavior with surprising ultranarrow energy gaps of 1.01-1.21 eV.
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Affiliation(s)
- Minghuey Shieh
- Department of Chemistry , National Taiwan Normal University , Taipei 11677 , Taiwan , Republic of China
| | - Yu-Hsin Liu
- Department of Chemistry , National Taiwan Normal University , Taipei 11677 , Taiwan , Republic of China
| | - Chung-Yi Huang
- Department of Chemistry , National Taiwan Normal University , Taipei 11677 , Taiwan , Republic of China
| | - Szu-Wei Chen
- Department of Chemistry , National Taiwan Normal University , Taipei 11677 , Taiwan , Republic of China
| | - Wen-Kai Cheng
- Department of Chemistry , National Taiwan Normal University , Taipei 11677 , Taiwan , Republic of China
| | - Li-Tzu Chien
- Department of Chemistry , National Taiwan Normal University , Taipei 11677 , Taiwan , Republic of China
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Zhang J, Wu S, Shan Y, Guo J, Yan S, Xiao S, Yang C, Shen J, Chen J, Liu L, Wu X. Distorted Monolayer ReS 2 with Low-Magnetic-Field Controlled Magnetoelectricity. ACS NANO 2019; 13:2334-2340. [PMID: 30735355 DOI: 10.1021/acsnano.8b09058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two dimensional (2D) materials possessing ferroelectric/ferromagnetic orders and especially low-magnetic-field controlled magnetoelectricity have great promise in spintronics and multistate data storage. However, ferroelectric and magnetoelectric (ME) dipoles in the atom-thick 2D materials are difficult to be realized due to structural inversion symmetry, thermal actuation, and depolarized field. To overcome these difficulties, the monolayer structure must possess an in-plane inversion asymmetry in order to provide out-of-plane ferroelectric polarization. Herein, crystal chemistry is adopted to engineer specific atomic displacement in monolayer ReS2 to change the crystal symmetry to induce out-of-plane ferroelectric polarization at room temperature. The cationic Re vacancy in the atom-displaced ReS2 monolayer causes spin polarization of two immediate neighbor sulfur atoms to generate magnetic ordering, and the ferroelectric distortion near the Re vacancy locally tunes the ferromagnetic order thereby triggering low-magnetic-field controlled ME polarization at about 28 K. As a result, 2D ME coupling multiferroics is achieved. Our results not only reveal a design methodology to attain coexistence of ferroelectric and ferromagnetic orders in 2D materials but also provide insights into magnetoelectricity in 2D materials.
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Affiliation(s)
- Jinlei Zhang
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Shuyi Wu
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Yun Shan
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
- China Key Laboratory of Advanced Functional Materials of Nanjing , Nanjing Xiaozhuang University , Nanjing 210093 , P.R. China
| | - JunHong Guo
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
- School of Optoelectronic Engineering and Grüenberg Research Centre , Nanjing University of Posts and Telecommunications , Nanjing 210093 , P.R. China
| | - Shuo Yan
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Shuyu Xiao
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Chunbing Yang
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Jiancang Shen
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Jian Chen
- Research Institute of Superconductor Electronics , Nanjing University , Nanjing 210093 , P.R. China
| | - Lizhe Liu
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
| | - Xinglong Wu
- National Laboratory of Solid State Microstructures and Department of Physics , Nanjing University , Nanjing 210093 , P.R. China
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10
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Liu W, Xu Y, He L, van der Laan G, Zhang R, Wang K. Experimental observation of dual magnetic states in topological insulators. SCIENCE ADVANCES 2019; 5:eaav2088. [PMID: 30783626 PMCID: PMC6368422 DOI: 10.1126/sciadv.aav2088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
Abstract
The recently discovered topological phase offers new possibilities for spintronics and condensed matter. Even insulating material exhibits conductivity at the edges of certain systems, giving rise to an anomalous quantum Hall effect and other coherent spin transport phenomena, in which heat dissipation is minimized, with potential uses for next-generation energy-efficient electronics. While the metallic surface states of topological insulators (TIs) have been extensively studied, direct comparison of the surface and bulk magnetic properties of TIs has been little explored. We report unambiguous evidence for distinctly enhanced surface magnetism in a prototype magnetic TI, Cr-doped Bi2Se3. Using synchrotron-based x-ray techniques, we demonstrate a "three-step transition" model, with a temperature window of ~15 K, where the TI surface is magnetically ordered while the bulk is not. Understanding the dual magnetization process has strong implications for defining a physical model of magnetic TIs and lays the foundation for applications to information technology.
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Affiliation(s)
- Wenqing Liu
- York-Nanjing Joint Center (YNJC) for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University, Nanjing 210093, China
- Department of Electronic Engineering, Royal Holloway University of London, Egham TW20 0EX, UK
| | - Yongbing Xu
- York-Nanjing Joint Center (YNJC) for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University, Nanjing 210093, China
- Department of Electronic Engineering, The University of York, York YO10 5DD, UK
| | - Liang He
- York-Nanjing Joint Center (YNJC) for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University, Nanjing 210093, China
- Department of Electrical and Computer Engineering, Department of Materials Science and Engineering, and Department of Physics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | - Rong Zhang
- Department of Electronic Engineering, Royal Holloway University of London, Egham TW20 0EX, UK
| | - Kang Wang
- Department of Electrical and Computer Engineering, Department of Materials Science and Engineering, and Department of Physics, University of California, Los Angeles, Los Angeles, CA 90095, USA
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11
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Spin-ARPES EUV Beamline for Ultrafast Materials Research and Development. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9030370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A new femtosecond, Extreme Ultraviolet (EUV), Time Resolved Spin-Angle Resolved Photo-Emission Spectroscopy (TR-Spin-ARPES) beamline was developed for ultrafast materials research and development. This 50-fs laser-driven, table-top beamline is an integral part of the “Ultrafast Spintronic Materials Facility”, dedicated to engineering ultrafast materials. This facility provides a fast and in-situ analysis and development of new materials. The EUV source based on high harmonic generation process emits 2.3 × 1011 photons/second (2.3 × 108 photons/pulse) at H23 (35.7 eV) and its photon energy ranges from 10 eV to 75 eV, which enables surface sensitive studies of the electronic structure dynamics. The EUV monochromator provides the narrow bandwidth of the EUV beamline while preserving its pulse duration in an energy range of 10–100 eV. Ultrafast surface photovoltaic effect with ~650 fs rise-time was observed in p-GaAs (100) from time-resolved ARPES spectra. The data acquisition time could be reduced by over two orders of magnitude by scaling the laser driver from 1 KHz, 4W to MHz, KW average power.
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12
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Singh A, Kamboj VS, Liu J, Llandro J, Duffy LB, Senanayak SP, Beere HE, Ionescu A, Ritchie DA, Hesjedal T, Barnes CHW. Systematic Study of Ferromagnetism in Cr xSb 2-xTe 3 Topological Insulator Thin Films using Electrical and Optical Techniques. Sci Rep 2018; 8:17024. [PMID: 30451885 PMCID: PMC6242999 DOI: 10.1038/s41598-018-35118-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/27/2018] [Indexed: 11/17/2022] Open
Abstract
Ferromagnetic ordering in a topological insulator can break time-reversal symmetry, realizing dissipationless electronic states in the absence of a magnetic field. The control of the magnetic state is of great importance for future device applications. We provide a detailed systematic study of the magnetic state in highly doped CrxSb2−xTe3 thin films using electrical transport, magneto-optic Kerr effect measurements and terahertz time domain spectroscopy, and also report an efficient electric gating of ferromagnetic order using the electrolyte ionic liquid [DEME][TFSI]. Upon increasing the Cr concentration from x = 0.15 to 0.76, the Curie temperature (Tc) was observed to increase by ~5 times to 176 K. In addition, it was possible to modify the magnetic moment by up to 50% with a gate bias variation of just ±3 V, which corresponds to an increase in carrier density by 50%. Further analysis on a sample with x = 0.76 exhibits a clear insulator-metal transition at Tc, indicating the consistency between the electrical and optical measurements. The direct correlation obtained between the carrier density and ferromagnetism - in both electrostatic and chemical doping - using optical and electrical means strongly suggests a carrier-mediated Ruderman-Kittel-Kasuya-Yoshida (RKKY) coupling scenario. Our low-voltage means of manipulating ferromagnetism, and consistency in optical and electrical measurements provides a way to realize exotic quantum states for spintronic and low energy magneto-electronic device applications.
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Affiliation(s)
- Angadjit Singh
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
| | - Varun S Kamboj
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Jieyi Liu
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Justin Llandro
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.,Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577, Japan
| | - Liam B Duffy
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom.,ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Science and Technology Facilities Council, Oxon, OX11 0QX, United Kingdom
| | - Satyaprasad P Senanayak
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.,Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Plastics Engineering and Technology (CIPET), B-25, CNI complex, Patia, Bhubaneswar, Odisha, 751024, India
| | - Harvey E Beere
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Adrian Ionescu
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - David A Ritchie
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom.
| | - Crispin H W Barnes
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
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13
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Pia AD, Lisi S, Luca OD, Warr DA, Lawrence J, Otrokov MM, Aliev ZS, Chulkov EV, Agostino RG, Arnau A, Papagno M, Costantini G. TCNQ Physisorption on the Topological Insulator Bi 2 Se 3. Chemphyschem 2018; 19:2405-2410. [PMID: 29847012 DOI: 10.1002/cphc.201800259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Indexed: 11/07/2022]
Abstract
Topological insulators are promising candidates for spintronic applications due to their topologically protected, spin-momentum locked and gapless surface states. The breaking of the time-reversal symmetry after the introduction of magnetic impurities, such as 3d transition metal atoms embedded in two-dimensional molecular networks, could lead to several phenomena interesting for device fabrication. The first step towards the fabrication of metal-organic coordination networks on the surface of a topological insulator is to investigate the adsorption of the pure molecular layer, which is the aim of this study. Here, the effect of the deposition of the electron acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules on the surface of a prototypical topological insulator, bismuth selenide (Bi2 Se3 ), is investigated. Scanning tunneling microscope images at low-temperature reveal the formation of a highly ordered two-dimensional molecular network. The essentially unperturbed electronic structure of the topological insulator observed by photoemission spectroscopy measurements demonstrates a negligible charge transfer between the molecular layer and the substrate. Density functional theory calculations confirm the picture of a weakly interacting adsorbed molecular layer. These results reveal significant potential of TCNQ for the realization of metal-organic coordination networks on the topological insulator surface.
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Affiliation(s)
- Ada Della Pia
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Simone Lisi
- Institut Néel, 25 Rue des Martyrs BP 166, 38042, Grenoble, France
| | - Oreste De Luca
- Dipartimento di Fisica, Università della Calabria, 87036, Arcavacata di Rende (CS), Italy
| | - Daniel A Warr
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - J Lawrence
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Mikhail M Otrokov
- Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20080, San Sebastián/Donostia, Spain
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Tomsk State University, 634050, Tomsk, Russia
| | - Ziya S Aliev
- Azerbaijan State Oil and Industry University, AZ1010, Baku, Azerbaijan
- Materials Science and Nanotechnology Department, Near East University, North Cyprus, Mersin 10, 99138, Nicosia, Turkey
| | - Evgueni V Chulkov
- Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20080, San Sebastián/Donostia, Spain
- Saint Petersburg State University, 198504, Saint Petersburg, Russia
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastian, Spain
| | - Raffaele G Agostino
- Dipartimento di Fisica, Università della Calabria, 87036, Arcavacata di Rende (CS), Italy
| | - Andrés Arnau
- Departamento de Física de Materiales UPV/EHU, Centro de Física de Materiales CFM-MPC and Centro Mixto CSIC-UPV/EHU, 20080, San Sebastián/Donostia, Spain
- Donostia International Physics Center (DIPC), 20018, Donostia-San Sebastian, Spain
| | - Marco Papagno
- Dipartimento di Fisica, Università della Calabria, 87036, Arcavacata di Rende (CS), Italy
| | - Giovanni Costantini
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
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14
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Zhu S, Meng D, Liang G, Shi G, Zhao P, Cheng P, Li Y, Zhai X, Lu Y, Chen L, Wu K. Proximity-induced magnetism and an anomalous Hall effect in Bi 2Se 3/LaCoO 3: a topological insulator/ferromagnetic insulator thin film heterostructure. NANOSCALE 2018; 10:10041-10049. [PMID: 29774918 DOI: 10.1039/c8nr02083c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Inducing magnetism in a topological insulator (TI) by exchange coupling with a ferromagnetic insulator (FMI) will break the time-reversal symmetry of topological surface states, offering possibilities to realize several predicted novel magneto-electric effects. Seeking suitable FMI materials is crucial for the coupling of heterojunctions, and yet is challenging as well and only a few kinds have been explored. In this report, we introduce epitaxial LaCoO3 thin films on a SrTiO3 substrate, which is an insulating ferromagnet with a Curie temperature of TC ∼ 85 K, to be combined with TIs for proximity coupling. Thin films of the prototype topological insulator, Bi2Se3, are successfully grown onto the (001) surface of LaCoO3/SrTiO3, forming a high-quality TI/FMI heterostructure with a sharp interface. The magnetic and transport measurements manifest the emergence of a ferromagnetic phase in Bi2Se3 films, with additional induced moments and a suppressed weak antilocalization effect, while preserving the carrier mobility of the intrinsic Bi2Se3 films at the same time. Moreover, a signal of an anomalous Hall effect is observed and persists up to temperatures above 100 K, paving the way towards spintronic device applications.
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Affiliation(s)
- Shanna Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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15
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Yilmaz T, Hines W, Alraddadi S, Budnick JI, Sinkovic B. Origin of the temperature dependence of the energy gap in Cr-doped Bi 2Se 3. Phys Chem Chem Phys 2018. [DOI: 10.1039/c7cp08049b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent progress in impurity-doped topological insulators has shown that the gap at the Dirac point shrinks with reducing temperature.
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Affiliation(s)
- Turgut Yilmaz
- Department of Physics, University of Connecticut
- Storrs
- USA
- Department of Physics, Science and Literature Faculty, Uludag University
- Bursa 16059
| | - William Hines
- Department of Physics, University of Connecticut
- Storrs
- USA
| | - Shoroog Alraddadi
- Department of Physics, Umm Al-Qura University
- Makkah 24382
- Kingdom of Saudi Arabia
| | | | - Boris Sinkovic
- Department of Physics, University of Connecticut
- Storrs
- USA
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16
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Sunderland TL, Berry JF. Metal-Metal Single Bonds with the Magnetic Anisotropy of Quadruple Bonds: A Systematic Series of Heterobimetallic Bismuth(II)-Rhodium(II) Formamidinate Complexes. Chemistry 2016; 22:18564-18571. [DOI: 10.1002/chem.201604007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Travis L. Sunderland
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Ave. Madison WI 53706 USA
| | - John F. Berry
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Ave. Madison WI 53706 USA
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17
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Atomic-level structural and chemical analysis of Cr-doped Bi2Se3 thin films. Sci Rep 2016; 6:26549. [PMID: 27221782 PMCID: PMC4879552 DOI: 10.1038/srep26549] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 05/04/2016] [Indexed: 11/18/2022] Open
Abstract
We present a study of the structure and chemical composition of the Cr-doped 3D topological insulator Bi2Se3. Single-crystalline thin films were grown by molecular beam epitaxy on Al2O3 (0001), and their structural and chemical properties determined on an atomic level by aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy. A regular quintuple layer stacking of the Bi2Se3 film is found, with the exception of the first several atomic layers in the initial growth. The spectroscopy data gives direct evidence that Cr is preferentially substituting for Bi in the Bi2Se3 host. We also show that Cr has a tendency to segregate at internal grain boundaries of the Bi2Se3 film.
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18
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Liu W, Zhou Q, Chen Q, Niu D, Zhou Y, Xu Y, Zhang R, Wang J, van der Laan G. Probing the Buried Magnetic Interfaces. ACS APPLIED MATERIALS & INTERFACES 2016; 8:5752-5757. [PMID: 26887429 DOI: 10.1021/acsami.5b11438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Understanding magnetism in ferromagnetic metal/semiconductor (FM/SC) heterostructures is important to the development of the new-generation spin field-effect transistor. Here, we report an element-specific X-ray magnetic circular dichroism study of the interfacial magnetic moments for two FM/SC model systems, namely, Co/GaAs and Ni/GaAs, which was enabled using a specially designed FM1/FM2/SC superstructure. We observed a robust room temperature magnetization of the interfacial Co, while that of the interfacial Ni was strongly diminished down to 5 K because of hybridization of the Ni d(eg) and GaAs sp(3) states. The validity of the selected method was confirmed by first-principles calculations, showing only small deviations (<0.02 and <0.07 μB/atom for Co/GaAs and Ni/GaAs, respectively) compared to the real FM/SC interfaces. Our work proved that the electronic structure and magnetic ground state of the interfacial FM2 is not altered when the topmost FM2 is replaced by FM1 and that this model is applicable generally for probing the buried magnetic interfaces in the advanced spintronic materials..
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Affiliation(s)
- Wenqing Liu
- York-Nanjing Joint Center for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University , Nanjing 210093, China
- Spintronics and Nanodevice Laboratory, Department of Electronics, University of York , York YO10 5DD, U.K
- Department of Physics, The University of Hong Kong , Pokfulam, Hong Kong
| | - Qionghua Zhou
- Department of Physics, Southeast University , Nanjing 211189, China
| | - Qian Chen
- Department of Physics, Southeast University , Nanjing 211189, China
| | - Daxin Niu
- Spintronics and Nanodevice Laboratory, Department of Electronics, University of York , York YO10 5DD, U.K
| | - Yan Zhou
- York-Nanjing Joint Center for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University , Nanjing 210093, China
- Department of Physics, The University of Hong Kong , Pokfulam, Hong Kong
| | - Yongbing Xu
- York-Nanjing Joint Center for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University , Nanjing 210093, China
- Spintronics and Nanodevice Laboratory, Department of Electronics, University of York , York YO10 5DD, U.K
| | - Rong Zhang
- York-Nanjing Joint Center for Spintronics and Nanoengineering, School of Electronics Science and Engineering, Nanjing University , Nanjing 210093, China
| | - Jinlan Wang
- Department of Physics, Southeast University , Nanjing 211189, China
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19
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Vasconcelos HMDN, Eddrief M, Zheng Y, Demaille D, Hidki S, Fonda E, Novikova A, Fujii J, Torelli P, Salles BR, Vobornik I, Panaccione G, de Oliveira AJA, Marangolo M, Vidal F. Magnetically Hard Fe3Se4 Embedded in Bi2Se3 Topological Insulator Thin Films Grown by Molecular Beam Epitaxy. ACS NANO 2016; 10:1132-1138. [PMID: 26653134 DOI: 10.1021/acsnano.5b06430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigated the structural, magnetic, and electronic properties of Bi2Se3 epilayers containing Fe grown on GaAs(111) by molecular beam epitaxy. It is shown that, in the window of growth parameters leading to Bi2Se3 epilayers with optimized quality, Fe atom clustering leads to the formation of FexSey inclusions. These objects have platelet shape and are embedded within Bi2Se3. Monoclinic Fe3Se4 is identified as the main secondary phase through detailed structural measurements. Due to the presence of the hard ferrimagnetic Fe3Se4 inclusions, the system exhibits a very large coercive field at low temperature and room temperature magnetic ordering. Despite this composite structure and the proximity of a magnetic phase, the surface electronic structure of Bi2Se3 is preserved, as shown by the persistence of a gapless Dirac cone at Γ.
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Affiliation(s)
- Hugo Menezes do Nascimento Vasconcelos
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
- Departamento de Física, Universidade Federal de São Carlos , CP 676, 13565-905 São Carlos, SP, Brazil
| | - Mahmoud Eddrief
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - Yunlin Zheng
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - Dominique Demaille
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - Sarah Hidki
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - Emiliano Fonda
- Synchrotron Soleil , L'Orme des Merisiers Saint-Aubin BP 48, 91192 Gif-sur-Yvette Cedex, France
| | - Anastasiia Novikova
- Synchrotron Soleil , L'Orme des Merisiers Saint-Aubin BP 48, 91192 Gif-sur-Yvette Cedex, France
| | - Jun Fujii
- Istituto Officina dei Materiali (IOM) - CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - Piero Torelli
- Istituto Officina dei Materiali (IOM) - CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - Benjamin Rache Salles
- Istituto Officina dei Materiali (IOM) - CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
- Instituto de Física, Universidade Federal do Rio de Janeiro , 21941-972 Rio de Janeiro, RJ, Brazil
| | - Ivana Vobornik
- Istituto Officina dei Materiali (IOM) - CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | - Giancarlo Panaccione
- Istituto Officina dei Materiali (IOM) - CNR, Laboratorio TASC, in Area Science Park, S.S.14, Km 163.5, I-34149 Trieste, Italy
| | | | - Massimiliano Marangolo
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
| | - Franck Vidal
- Sorbonne Universités , UPMC Univ Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, F-75005 Paris, France
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