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Ravichandran J, Serrao CR, Efetov DK, Yi D, Oh YS, Cheong SW, Ramesh R, Kim P. Ambipolar transport and magneto-resistance crossover in a Mott insulator, Sr 2IrO 4. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:505304. [PMID: 27792666 DOI: 10.1088/0953-8984/28/50/505304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electric field effect (EFE) controlled magnetoelectric transport in thin films of undoped and La-doped Sr2IrO4 (SIO) is investigated using ionic liquid gating. The temperature dependent resistance measurements exhibit insulating behavior in chemically and EFE doped samples with the band filling up to 10%. The ambipolar transport across the Mott gap is demonstrated by EFE tuning of the channel resistance and chemical doping. We observe a crossover from high temperature negative to low temperature positive magnetoresistance around ∼80-90 K, irrespective of the filling. This temperature and magnetic field dependent crossover is discussed in the light of conduction mechanisms of SIO, especially variable range hopping (VRH), and its relevance to the insulating ground state of SIO.
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Affiliation(s)
- J Ravichandran
- Department of Physics, Columbia University, New York, NY 10027, USA
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Liao J, Ou Y, Feng X, Yang S, Lin C, Yang W, Wu K, He K, Ma X, Xue QK, Li Y. Observation of Anderson localization in ultrathin films of three-dimensional topological insulators. PHYSICAL REVIEW LETTERS 2015; 114:216601. [PMID: 26066450 DOI: 10.1103/physrevlett.114.216601] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Indexed: 06/04/2023]
Abstract
Anderson localization, the absence of diffusive transport in disordered systems, has been manifested as hopping transport in numerous electronic systems, whereas in recently discovered topological insulators it has not been directly observed. Here, we report experimental demonstration of a crossover from diffusive transport in the weak antilocalization regime to variable range hopping transport in the Anderson localization regime with ultrathin (Bi_{1-x}Sb_{x})_{2}Te_{3} films. As disorder becomes stronger, negative magnetoconductivity due to the weak antilocalization is gradually suppressed, and eventually, positive magnetoconductivity emerges when the electron system becomes strongly localized. This work reveals the critical role of disorder in the quantum transport properties of ultrathin topological insulator films, in which theories have predicted rich physics related to topological phase transitions.
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Affiliation(s)
- Jian Liao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yunbo Ou
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Xiao Feng
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Shuo Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chaojing Lin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wenmin Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Kehui Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Ke He
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Xucun Ma
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Qi-Kun Xue
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Yongqing Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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Vaknin A, Frydman A, Ovadyahu Z, Pollak M. High-field magnetoconductance in Anderson insulators. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:13604-13610. [PMID: 9985272 DOI: 10.1103/physrevb.54.13604] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Lin YL, Nori F. Analytical results on quantum interference and magnetoconductance for strongly localized electrons in a magnetic field: Exact summation of forward-scattering paths. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:15543-15562. [PMID: 9983387 DOI: 10.1103/physrevb.53.15543] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Lin YL, Nori F. Strongly localized electrons in a magnetic field: Exact results on quantum interference and magnetoconductance. PHYSICAL REVIEW LETTERS 1996; 76:4580-4583. [PMID: 10061327 DOI: 10.1103/physrevlett.76.4580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Friedman JR, Zhang Y, Dai P, Sarachik MP. Magnetic-field-induced crossover from Mott variable-range hopping to weakly insulating behavior. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:9528-9531. [PMID: 9982491 DOI: 10.1103/physrevb.53.9528] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Medina E, Kardar M, Rangel R. Magnetoconductance anisotropy and interference effects in variable-range hopping. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:7663-7672. [PMID: 9982210 DOI: 10.1103/physrevb.53.7663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bleibaum O, Böttger H, Bryksin VV, Schulz F. Hopping transport in a magnetic field: Kadanoff-Baym-Keldysh approach and magnetoconductivity. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:14020-14034. [PMID: 9978327 DOI: 10.1103/physrevb.51.14020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Hsu SY, Valles JM. Observation of a well defined transition from weak to strong localization in two dimensions. PHYSICAL REVIEW LETTERS 1995; 74:2331-2334. [PMID: 10057901 DOI: 10.1103/physrevlett.74.2331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Zhang Y, Sarachik MP. Two-parameter scaling of the hopping conductivity of n-type CdSe. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:2580-2583. [PMID: 9979017 DOI: 10.1103/physrevb.51.2580] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Zhang Y, Dai P, Kam I, Sarachik MP. Empirical relation between longitudinal and transverse transport in insulating n-CdSe. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:5032-5033. [PMID: 10011440 DOI: 10.1103/physrevb.49.5032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Böttger H, Bryksin VV, Schulz F. Hopping conduction in disordered systems in the presence of a magnetic field: Linearized rate equation and magnetoresistance. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:2447-2459. [PMID: 10011078 DOI: 10.1103/physrevb.49.2447] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Dai P, Friedman JR, Sarachik MP. Hopping conduction in doped silicon: The apparent absence of quantum interference. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:4875-4878. [PMID: 10008981 DOI: 10.1103/physrevb.48.4875] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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