1
|
Deng P, Grutter A, Han Y, Holtz ME, Zhang P, Quarterman P, Pan S, Qi S, Qiao Z, Wang KL. Topological Surface State Annihilation and Creation in SnTe/Cr x(BiSb) 2-xTe 3 Heterostructures. NANO LETTERS 2022; 22:5735-5741. [PMID: 35850534 DOI: 10.1021/acs.nanolett.2c00774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Topological surface states are a new class of electronic states with novel properties, including the potential for annihilation between surface states from two topological insulators at a common interface. Here, we report the annihilation and creation of topological surface states in the SnTe/Crx(BiSb)2-xTe3 (CBST) heterostructures as evidenced by magneto-transport, polarized neutron reflectometry, and first-principles calculations. Our results show that topological surface states are induced in the otherwise topologically trivial two-quintuple-layers thick CBST when interfaced with SnTe, as a result of the surface state annihilation at the SnTe/CBST interface. Moreover, we unveiled systematic changes in the transport behaviors of the heterostructures with respect to changing Fermi level and thickness. Our observation of surface state creation and annihilation demonstrates a promising way of designing and engineering topological surface states for dissipationless electronics.
Collapse
Affiliation(s)
- Peng Deng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
- Beijing Academy of Quantum Information Science, Beijing 100193, China
| | - Alexander Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Maryland 20899-6102, United States
| | - Yulei Han
- ICQD, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Anhui 230026, China
| | - Megan E Holtz
- Materials Measurement Laboratory, National Institute of Standards and Technology, Maryland 20899-6102, United States
| | - Peng Zhang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
| | - Patrick Quarterman
- NIST Center for Neutron Research, National Institute of Standards and Technology, Maryland 20899-6102, United States
| | - Shuaihang Pan
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095, United States
| | - Shifei Qi
- ICQD, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Anhui 230026, China
- College of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Hebei 050024, China
| | - Zhenhua Qiao
- NIST Center for Neutron Research, National Institute of Standards and Technology, Maryland 20899-6102, United States
| | - Kang L Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, California 90095, United States
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| |
Collapse
|
2
|
Bhattacharjee N, Mahalingam K, Fedorko A, Lauter V, Matzelle M, Singh B, Grutter A, Will-Cole A, Page M, McConney M, Markiewicz R, Bansil A, Heiman D, Sun NX. Topological Antiferromagnetic Van der Waals Phase in Topological Insulator/Ferromagnet Heterostructures Synthesized by a CMOS-Compatible Sputtering Technique. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108790. [PMID: 35132680 DOI: 10.1002/adma.202108790] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Breaking time-reversal symmetry by introducing magnetic order, thereby opening a gap in the topological surface state bands, is essential for realizing useful topological properties such as the quantum anomalous Hall and axion insulator states. In this work, a novel topological antiferromagnetic (AFM) phase is created at the interface of a sputtered, c-axis-oriented, topological insulator/ferromagnet heterostructure-Bi2 Te3 /Ni80 Fe20 because of diffusion of Ni in Bi2 Te3 (Ni-Bi2 Te3 ). The AFM property of the Ni-Bi2 Te3 interfacial layer is established by observation of spontaneous exchange bias in the magnetic hysteresis loop and compensated moments in the depth profile of the magnetization using polarized neutron reflectometry. Analysis of the structural and chemical properties of the Ni-Bi2 Te3 layer is carried out using selected-area electron diffraction, electron energy loss spectroscopy, and X-ray photoelectron spectroscopy. These studies, in parallel with first-principles calculations, indicate a solid-state chemical reaction that leads to the formation of Ni-Te bonds and the presence of topological antiferromagnetic (AFM) compound NiBi2 Te4 in the Ni-Bi2 Te3 interface layer. The Neél temperature of the Ni-Bi2 Te3 layer is ≈63 K, which is higher than that of typical magnetic topological insulators (MTIs). The presented results provide a pathway toward industrial complementary metal-oxide-semiconductor (CMOS)-process-compatible sputtered-MTI heterostructures, leading to novel materials for topological quantum devices.
Collapse
Affiliation(s)
- Nirjhar Bhattacharjee
- Northeastern University, Department of Electrical and Computer Engineering, Boston, MA, 02115, USA
| | - Krishnamurthy Mahalingam
- Air Force Research Laboratory, Nano-electronic Materials Branch, Wright Patterson Air Force Base, Boston, OH, 05433, USA
| | - Adrian Fedorko
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Valeria Lauter
- Quantum Condensed Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Boston, TN, 37831, USA
| | - Matthew Matzelle
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Bahadur Singh
- Tata Institute of Fundamental Research, Department of Condensed Matter Physics and Materials Science, Mumbai, 400005, India
| | - Alexander Grutter
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Alexandria Will-Cole
- Northeastern University, Department of Electrical and Computer Engineering, Boston, MA, 02115, USA
| | - Michael Page
- Air Force Research Laboratory, Nano-electronic Materials Branch, Wright Patterson Air Force Base, Boston, OH, 05433, USA
| | - Michael McConney
- Air Force Research Laboratory, Nano-electronic Materials Branch, Wright Patterson Air Force Base, Boston, OH, 05433, USA
| | - Robert Markiewicz
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Arun Bansil
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
| | - Don Heiman
- Northeastern University, Department of Physics, Boston, MA, 02115, USA
- Plasma Science and Fusion Center, MIT, Cambridge, MA, 02139, USA
| | - Nian Xiang Sun
- Northeastern University, Department of Electrical and Computer Engineering, Boston, MA, 02115, USA
| |
Collapse
|
3
|
Liu J, Hesjedal T. Magnetic Topological Insulator Heterostructures: A Review. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021:e2102427. [PMID: 34665482 DOI: 10.1002/adma.202102427] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/05/2021] [Indexed: 06/13/2023]
Abstract
Topological insulators (TIs) provide intriguing prospects for the future of spintronics due to their large spin-orbit coupling and dissipationless, counter-propagating conduction channels in the surface state. The combination of topological properties and magnetic order can lead to new quantum states including the quantum anomalous Hall effect that was first experimentally realized in Cr-doped (Bi,Sb)2 Te3 films. Since magnetic doping can introduce detrimental effects, requiring very low operational temperatures, alternative approaches are explored. Proximity coupling to magnetically ordered systems is an obvious option, with the prospect to raise the temperature for observing the various quantum effects. Here, an overview of proximity coupling and interfacial effects in TI heterostructures is presented, which provides a versatile materials platform for tuning the magnetic and topological properties of these exciting materials. An introduction is first given to the heterostructure growth by molecular beam epitaxy and suitable structural, electronic, and magnetic characterization techniques. Going beyond transition-metal-doped and undoped TI heterostructures, examples of heterostructures are discussed, including rare-earth-doped TIs, magnetic insulators, and antiferromagnets, which lead to exotic phenomena such as skyrmions and exchange bias. Finally, an outlook on novel heterostructures such as intrinsic magnetic TIs and systems including 2D materials is given.
Collapse
Affiliation(s)
- Jieyi Liu
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Thorsten Hesjedal
- Clarendon Laboratory, Department of Physics University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| |
Collapse
|
4
|
Tian F, Zhang Y, Zhou C, Zhao Q, Yu Z, Murtaza A, Zuo W, Yang S, Song X. Giant Vertical Magnetization Shift Caused by Field-Induced Ferromagnetic Spin Reconfiguration in Ni 50Mn 36Ga 14 Alloy. MATERIALS 2020; 13:ma13214701. [PMID: 33105593 PMCID: PMC7659958 DOI: 10.3390/ma13214701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/13/2020] [Accepted: 10/19/2020] [Indexed: 11/16/2022]
Abstract
Vertical magnetization shift (VMS) is a special type of exchange bias effect that may lead to a revolution in future ultrahigh-density magnetic recording technology. However, there are very few reports focusing on the performance of VMS due to the unclear mechanism. In this paper, a giant vertical magnetization shift (ME) of 6.34 emu/g is reported in the Ni50Mn36Ga14 alloy. The VMS can be attributed to small ferromagnetic ordered regions formed by spin reconfiguration after field cooling, which are embedded in an antiferromagnetic matrix. The strong cooling-field dependence, temperature dependence, and training effect all corroborate the presence of spin reconfiguration and its role in the VMS. This work can enrich VMS research and increase its potential in practical applications as well.
Collapse
|