Competition between Weak Localization and Antilocalization in Topological Surface States
Competition between Weak Localization and Antilocalization in Topological Surface States
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DOI：
10.1103/physrevlett.107.076801
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发表时间：
2011-08-08
影响因子：
8.6
通讯作者：
Shen, Shun-Qing
中科院分区：
文献类型：
--
作者：
Lu, Hai-Zhou;Shi, Junren;Shen, Shun-Qing
针对磁性掺杂拓扑绝缘体的表面态，给出了一个磁导率公式。它揭示了当通过磁性掺杂在狄拉克点处打开能隙时，量子输运中弱局域化和弱反局域化的竞争效应。研究发现，尽管随机磁散射总是使系统从辛类转变为幺正类，但能隙可能会引发从弱反局域化到弱局域化的转变，该转变可通过费米能或能隙进行调节。这种转变呈现出一个独特的特征，它表征了在量子扩散区域中狄拉克点处能隙打开的拓扑绝缘体的表面态。
A magnetoconductivity formula is presented for the surface states of a magnetically doped topological insulator. It reveals a competing effect of weak localization and weak antilocalization in quantum transport when an energy gap is opened at the Dirac point by magnetic doping. It is found that, while random magnetic scattering always drives the system from the symplectic to the unitary class, the gap could induce a crossover from weak antilocalization to weak localization, tunable by the Fermi energy or the gap. This crossover presents a unique feature characterizing the surface states of a topological insulator with the gap opened at the Dirac point in the quantum diffusion regime.