Gracia-Abad Rubén, Sangiao Soraya, Bigi Chiara, Kumar Chaluvadi Sandeep, Orgiani Pasquale, De Teresa José María
Departamento de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain.
Laboratorio de Microscopías Avanzadas (LMA), Universidad de Zaragoza, 50018 Zaragoza, Spain.
Nanomaterials (Basel). 2021 Apr 22;11(5):1077. doi: 10.3390/nano11051077.
Topological insulators are materials with time-reversal symmetric states of matter in which an insulating bulk is surrounded by protected Dirac-like edge or surface states. Among topological insulators, Bi2Se3 has attracted special attention due to its simple surface band structure and its relatively large band gap that should enhance the contribution of its surface to transport, which is usually masked by the appearance of defects. In order to avoid this difficulty, several features characteristic of topological insulators in the quantum regime, such as the weak-antilocalization effect, can be explored through magnetotransport experiments carried out on thin films of this material. Here, we review the existing literature on the magnetotransport properties of Bi2Se3 thin films, paying thorough attention to the weak-antilocalization effect, which is omnipresent no matter the film quality. We carefully follow the different situations found in reported experiments, from the most ideal situations, with a strong surface contribution, towards more realistic cases where the bulk contribution dominates. We have compared the transport data found in literature to shed light on the intrinsic properties of Bi2Se3, finding a clear relationship between the mobility and the phase coherence length of the films that could trigger further experiments on transport in topological systems.
拓扑绝缘体是具有时间反演对称物态的材料，其绝缘体能带被受保护的类狄拉克边缘或表面态所包围。在拓扑绝缘体中，Bi2Se3因其简单的表面能带结构和相对较大的带隙而备受关注，较大的带隙应能增强其表面对输运的贡献，而这种贡献通常会被缺陷的出现所掩盖。为了避免这一困难，可以通过对这种材料的薄膜进行磁输运实验来探索量子体系中拓扑绝缘体的一些特征，比如弱反局域化效应。在此，我们回顾了关于Bi2Se3薄膜磁输运性质的现有文献，特别关注弱反局域化效应，无论薄膜质量如何，该效应都普遍存在。我们仔细梳理了已报道实验中发现的不同情况，从表面贡献占主导的最理想情况，到体贡献占主导的更实际情况。我们比较了文献中找到的输运数据，以阐明Bi2Se3的本征性质，发现了薄膜迁移率与相位相干长度之间的明确关系，这可能会引发对拓扑体系中输运的进一步实验。
