Axion Insulator State in Hundred-Nanometer-Thick Magnetic Topological Insulator Sandwich Heterostructures

Fuente: arXiv
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Main Authors: Zhuo, Deyi, Yan, Zi-Jie, Sun, Zi-Ting, Zhou, Ling-Jie, Zhao, Yi-Fan, Zhang, Ruoxi, Mei, Ruobing, Yi, Hemian, Wang, Ke, Chan, Moses H. W., Liu, Chao-Xing, Law, K. T., Chang, Cui-Zu
Format: Preprint
Published: 2023
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author Zhuo, Deyi
Yan, Zi-Jie
Sun, Zi-Ting
Zhou, Ling-Jie
Zhao, Yi-Fan
Zhang, Ruoxi
Mei, Ruobing
Yi, Hemian
Wang, Ke
Chan, Moses H. W.
Liu, Chao-Xing
Law, K. T.
Chang, Cui-Zu
author_facet Zhuo, Deyi
Yan, Zi-Jie
Sun, Zi-Ting
Zhou, Ling-Jie
Zhao, Yi-Fan
Zhang, Ruoxi
Mei, Ruobing
Yi, Hemian
Wang, Ke
Chan, Moses H. W.
Liu, Chao-Xing
Law, K. T.
Chang, Cui-Zu
contents An axion insulator is a three-dimensional (3D) topological insulator (TI), in which the bulk maintains the time-reversal symmetry or inversion symmetry but the surface states are gapped by surface magnetization. The axion insulator state has been observed in molecular beam epitaxy (MBE)-grown magnetically doped TI sandwiches and exfoliated intrinsic magnetic TI MnBi2Te4 flakes with an even number layer. All these samples have a thickness of ~10 nm, near the 2D-to-3D boundary. The coupling between the top and bottom surface states in thin samples may hinder the observation of quantized topological magnetoelectric response. Here, we employ MBE to synthesize magnetic TI sandwich heterostructures and find that the axion insulator state persists in a 3D sample with a thickness of ~106 nm. Our transport results show that the axion insulator state starts to emerge when the thickness of the middle undoped TI layer is greater than ~3 nm. The 3D hundred-nanometer-thick axion insulator provides a promising platform for the exploration of the topological magnetoelectric effect and other emergent magnetic topological states, such as the high-order TI phase.
format Preprint
id arxiv_https___arxiv_org_abs_2306_13016
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Axion Insulator State in Hundred-Nanometer-Thick Magnetic Topological Insulator Sandwich Heterostructures
Zhuo, Deyi
Yan, Zi-Jie
Sun, Zi-Ting
Zhou, Ling-Jie
Zhao, Yi-Fan
Zhang, Ruoxi
Mei, Ruobing
Yi, Hemian
Wang, Ke
Chan, Moses H. W.
Liu, Chao-Xing
Law, K. T.
Chang, Cui-Zu
Mesoscale and Nanoscale Physics
Materials Science
An axion insulator is a three-dimensional (3D) topological insulator (TI), in which the bulk maintains the time-reversal symmetry or inversion symmetry but the surface states are gapped by surface magnetization. The axion insulator state has been observed in molecular beam epitaxy (MBE)-grown magnetically doped TI sandwiches and exfoliated intrinsic magnetic TI MnBi2Te4 flakes with an even number layer. All these samples have a thickness of ~10 nm, near the 2D-to-3D boundary. The coupling between the top and bottom surface states in thin samples may hinder the observation of quantized topological magnetoelectric response. Here, we employ MBE to synthesize magnetic TI sandwich heterostructures and find that the axion insulator state persists in a 3D sample with a thickness of ~106 nm. Our transport results show that the axion insulator state starts to emerge when the thickness of the middle undoped TI layer is greater than ~3 nm. The 3D hundred-nanometer-thick axion insulator provides a promising platform for the exploration of the topological magnetoelectric effect and other emergent magnetic topological states, such as the high-order TI phase.
title Axion Insulator State in Hundred-Nanometer-Thick Magnetic Topological Insulator Sandwich Heterostructures
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2306.13016