Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2023 May 5;14(1):2596. doi: 10.1038/s41467-023-38256-4.
The interplay between quantum interference, electron-electron interaction (EEI), and disorder is one of the central themes of condensed matter physics. Such interplay can cause high-order magnetoconductance (MC) corrections in semiconductors with weak spin-orbit coupling (SOC). However, it remains unexplored how the magnetotransport properties are modified by the high-order quantum corrections in the electron systems of symplectic symmetry class, which include topological insulators (TIs), Weyl semimetals, graphene with negligible intervalley scattering, and semiconductors with strong SOC. Here, we extend the theory of quantum conductance corrections to two-dimensional (2D) electron systems with the symplectic symmetry, and study experimentally such physics with dual-gated TI devices in which the transport is dominated by highly tunable surface states. We find that the MC can be enhanced significantly by the second-order interference and the EEI effects, in contrast to the suppression of MC for the systems with orthogonal symmetry. Our work reveals that detailed MC analysis can provide deep insights into the complex electronic processes in TIs, such as the screening and dephasing effects of localized charge puddles, as well as the related particle-hole asymmetry.
量子干涉、电子-电子相互作用（EEI）和无序之间的相互作用是凝聚态物理的核心主题之一。这种相互作用会导致弱自旋轨道耦合（SOC）半导体中的高阶磁导率（MC）修正。然而，由辛对称类电子系统中的高阶量子修正如何改变磁输运性质仍未得到探索，辛对称类电子系统包括拓扑绝缘体（TI）、外尔半金属、谷间散射可忽略不计的石墨烯和 SOC 较强的半导体。在这里，我们将量子电导修正理论扩展到具有辛对称性的二维（2D）电子系统，并通过双栅 TI 器件实验研究了这种物理现象，其中传输主要由高度可调谐的表面态主导。我们发现，与正交对称系统中 MC 的抑制相反，二阶干涉和 EEI 效应可以显著增强 MC。我们的工作表明，详细的 MC 分析可以深入了解 TI 中的复杂电子过程，例如局部电荷液滴的屏蔽和退相位效应，以及相关的粒子-空穴不对称性。
