Enhanced electron dephasing in three-dimensional topological insulators

ORAL

Abstract

Study of the dephasing in electronic systems is not only important for probing the nature of their ground states, but also crucial to harnessing the quantum coherence for information processing. In contrast to well-studied conventional metals and semiconductors, it remains unclear which mechanism is mainly responsible for electron dephasing in three-dimensional topological insulators (TIs). Here, we report on using weak antilocalization effect to measure the dephasing rates in highly tunable (Bi,Sb)2Te3 thin films. As the transport is varied from a bulk-conducting regime to surface-dominant transport, the dephasing rate is observed to evolve from a linear temperature dependence to a sublinear power-law dependence. Although the former is consistent with the Nyquist electron-electron interactions commonly seen in ordinary 2D systems, the latter leads to enhanced electron dephasing at low temperatures and is attributed to the coupling between the surface states and the localized charge puddles in the bulk of 3D TIs.

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Presenters

  • Jian Liao

    • Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences

Authors

  • Jian Liao

    • Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences

  • Yunbo Ou

    • Physics, Massachusetts Institute of Technology
    • Plasma Science and Fusion Center and Francis Bitter Magnet Laboratory
    • Plasma Science and Fusion Center and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology
    • State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University

  • Haiwen Liu

    • Department of Physics, Beijing Normal University
    • Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University
    • Beijing Normal Univ

  • Ke He

    • Tsinghua Univ
    • Department of Physics, Tsinghua University
    • Tsinghua University
    • State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University

  • Xucun Ma

    • Department of Physics, Tsinghua University, Beijing 100084, China
    • State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University

  • Qikun Xue

    • Physics Department, Tsinghua University
    • Department of Physics, Tsinghua University
    • State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua Univ.
    • Tsinghua University
    • State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University

  • Yongqing Li

    • Institute of Physics, Chinese Academy of Sciences
    • Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences