Conduction of surface electrons in a topological insulator with spatially random magnetization

Kudła, S.; Dyrdał, A.; Dugaev, V. K.; Berakdar, Jamal; Barnaś, J.

doi:10.1103/physrevb.100.205428

Cited by 6 publications

(5 citation statements)

References 44 publications

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“…Recently there have been more theoretical interests on the effect of magnetic disorder on the QAH effect [10][11][12][13][14], but a thorough experimental investigation has been lacking. The main reason lies in the fact that magnetic disorder is introduced by the random deposition of magnetic dopants during sample growth, probably with a Gaussian-like distribution [8,10], thus it is difficult to control the strength of magnetic disorder.…”

Section: A Experimental Methodologymentioning

confidence: 99%

“…We propose that the transmission between the edge states of neighboring domains plays the most crucial role in the quantum transport process. In a macroscopic QAH sample, magnetic disorders lead to spatially separated and randomly distributed magnetic domains [7][8][9][10][11][12][13][14][15]. Under such situation, charge transport is mainly determined by two quantities, the average distance λ between neighboring domains and the decay length ξ of the chiral edge state at domain boundaries.…”

Section: E Edge State Transmission Modelmentioning

confidence: 99%

“…Therefore, magnetic TI is highly unique for exploring disorder-related magnetic and topological quantum phenomena [10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

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Distinct Quantum Anomalous Hall Ground States Induced by Magnetic Disorders

Liu

Feng

et al. 2020

Phys. Rev. X

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The quantum anomalous Hall (QAH) effect in magnetic topological insulator (TI) represents a new state of matter originated from the interplay between topology and magnetism. The defining characteristics of the QAH ground state are the quantized Hall resistivity (ρyx) and vanishing longitudinal resistivity (ρxx) in the absence of external magnetic field. A fundamental question concerning the QAH effect is whether it is merely a zero-magnetic-field quantum Hall (QH) effect, or if it can host unique quantum phases and phase transitions that are unavailable elsewhere. The most dramatic departure of the QAH systems from other QH systems lies in the strong magnetic disorders that induce spatially random magnetization. Because disorder and magnetism play pivotal roles in the phase diagram of two-dimensional electron systems, the high degree of magnetic disorders in QAH systems may create novel phases and quantum critical phenomena. In this work, we perform systematic transport studies of a series of magnetic TIs with varied strength of magnetic disorders. We find that the ground state of QAH effect can be categorized into two distinct classes: the QAH insulator and anomalous Hall (AH) insulator phases, as the zero-magnetic-field counterparts of the QH liquid and Hall insulator in the QH systems. In the low disorder limit of the QAH insulator regime, we observe a universal quantized longitudinal resistance ρxx = h/e 2 at the coercive field. In the AH insulator regime, we find that a magnetic field can drive it to the QAH insulator phase through a quantum critical point with distinct scaling behaviors from that in the QH phase transition. We propose that the transmission between chiral edge states at domain boundaries, tunable by disorder and magnetic fields, is the key for determining the QAH ground state.

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Section: A Experimental Methodologymentioning

confidence: 99%

Section: E Edge State Transmission Modelmentioning

confidence: 99%

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Distinct Quantum Anomalous Hall Ground States Induced by Magnetic Disorders

Liu

Feng

et al. 2020

Phys. Rev. X

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“…近年来, 理论上在这方面的研究取得了许多进展, 例如北京大学谢心澄团队 [46] 考虑磁无序和空间反演对称性, 提出了量子反常霍尔平台相变过程可能会遵循BKT相变机制. 美国加州理工大学Alicea团队 [47] 考虑磁性无序和反射对称性, 发现无序会引起一类名为量子反常宇称霍尔相的新型拓扑物态, 并提出可以通过测量量子化电导的方式对其进行探测. 此外, 除了关于磁性拓扑绝缘体本身无序性问题的讨论, 在其组成的异质结中的无序性问题也受到广泛关注, 特别是近年来关于能否利用量子反常霍尔薄膜-超导体异质结实现手征马约拉纳边缘模的实验在国际上引起了广泛的争议 [135] .…”

Section: 磁无序引起的不同量子反常霍尔基态unclassified

Quantum transport phenomena in magnetic topological insulators

Liu¹,

Wang²

2023

Acta Phys. Sin.

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Magnetic topological insulators have been a significant focus in the research of condensed matter physics over the past decade. The intricate interplay between the nontrivial band topology and spin, orbit, charge, and dimensionality degrees of freedom can give rise to a plethora of exotic topological quantum states and topological phase transitions. Measuring the transport properties of magnetic topological insulators is a crucial approach to exploring their exotic properties, which bears significant scientific importance in deepening our understanding of topological quantum states. Simultaneously, it also holds substantial potential for application in the development of novel low-power electronic devices. This article reviews the recent experimental advancements in transport studies of magnetic topological insulators in the past few years, encompassing the quantum anomalous Hall effect and topological quantum phase transitions in magnetically doped topological insulators, the quantum anomalous Hall phase, axion insulator phase and Chern insulator phase in intrinsic antiferromagnetic topological insulator MnBi<sub>2</sub>Te<sub>4</sub>, as well as the helical phase emerged from the Chern insulator in pulsed high magnetic fields. Finally, this article analyzes the future direction of development in magnetic topological insulators and the transport phenomena that remain to be understood in these systems, offering insights and perspectives on the potential breakthroughs to be achieved in this area of research.

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“…Electron scattering by impurities yields spectral features, such as circular s-wave resonances, that can be targeted by scanning tunnelling experiments (see reference 8 and references therein). Theoretical treatments of many impurities are often based on the self-consistent Born approximation (SCBA) [11][12][13][14][15][16][17][18][19] . In the SCBA the imaginary part of the self-energy in the bare Green function is replaced by the self-energy of the full Green function, that renders the problem self-consistent.…”

mentioning

confidence: 99%

Many-impurity scattering on the surface of a topological insulator

Vicario

Baba

Díaz

et al. 2021

Sci Rep

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We theoretically address the impact of a random distribution of non-magnetic impurities on the electron states formed at the surface of a topological insulator. The interaction of electrons with the impurities is accounted for by a separable pseudo-potential method that allows us to obtain closed expressions for the density of states. Spectral properties of surface states are assessed by means of the Green’s function averaged over disorder realisations. For comparison purposes, the configurationally averaged Green’s function is calculated by means of two different self-consistent methods, namely the self-consistent Born approximation (SCBA) and the coherent potential approximation (CPA). The latter is often regarded as the best single-site theory for the study of the spectral properties of disordered systems. However, although a large number of works employ the SCBA for the analysis of many-impurity scattering on the surface of a topological insulator, CPA studies of the same problem are scarce in the literature. In this work, we find that the SCBA overestimates the impact of the random distribution of impurities on the spectral properties of surface states compared to the CPA predictions. The difference is more pronounced when increasing the magnitude of the disorder.

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Conduction of surface electrons in a topological insulator with spatially random magnetization

Cited by 6 publications

References 44 publications

Distinct Quantum Anomalous Hall Ground States Induced by Magnetic Disorders

Distinct Quantum Anomalous Hall Ground States Induced by Magnetic Disorders

Quantum transport phenomena in magnetic topological insulators

Many-impurity scattering on the surface of a topological insulator

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