Transport in topological insulators with bulk-surface coupling: Interference corrections and conductance fluctuations
Transport in topological insulators with bulk-surface coupling: Interference corrections and conductance fluctuations
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DOI：
10.1103/physrevb.98.165408
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发表时间：
2018-10
影响因子：
3.7
通讯作者：
H. Velkov;G. Bremm;T. Micklitz;G. Schwiete
中科院分区：
文献类型：
--
作者：
H. Velkov;G. Bremm;T. Micklitz;G. Schwiete
由于生产具有纯表面态传导的 Bi$_2$Se$_3$ 族拓扑绝缘体 (TI) 的实验困难，我们研究了块体对门控 TI 薄膜低温传输特性的影响。我们特别关注干扰校正，即弱定位（WL）或弱反定位（WAL），以及基于有效低能哈密顿量的电导波动（CF）。利用图解微扰理论，我们首先分别分析体积和表面，然后讨论引入隧道耦合时的 WL/WAL 和 CF。我们识别耦合系统的相关软扩散模式，并利用这种洞察力对各种参数范围内的干扰校正和电导波动进行同时预测。结果强烈表明，这两个量的组合测量可以更好地理解具有体表面耦合的薄 TI 薄膜中低温传输过程的物理原理。
Motivated by the experimental difficulty to produce topological insulators (TIs) of the Bi$_2$Se$_3$ family with pure surface-state conduction, we study the effect that the bulk can have on the low-temperature transport properties of gated thin TI films. In particular, we focus on interference corrections, namely weak localization (WL) or weak-antilocalization (WAL), and conductance fluctuations (CFs) based on an effective low-energy Hamiltonian. Utilizing diagrammatic perturbation theory we first analyze the bulk and the surface separately and subsequently discuss WL/WAL and CFs when a tunneling-coupling is introduced. We identify the relevant soft diffusion modes of the coupled system and use this insight to make simultaneous predictions for both interference corrections and conductance fluctuations in various parameter regimes. The results strongly suggest that the combined measurement of both quantities can provide an improved understanding of the physics underlying the low-temperature transport processes in thin TI films with bulk-surface coupling.