绘制 Bi₂Se₃ 的三维表面电势图。

Mapping the 3D surface potential in Bi₂Se₃.

机构信息

Materials Science & Engineering Graduate Program, Texas Materials Institute, University of Texas at Austin, 204 E. Dean Keeton Street, Stop C2201, Austin, Texas 78712, USA.

出版信息

Nat Commun. 2013;4:2277. doi: 10.1038/ncomms3277.

DOI:10.1038/ncomms3277

PMID:23912773

Abstract

Bi₂Se₃ initially emerged as a particularly promising host of topological physics. However, in actual materials, several issues have been uncovered including strong surface band bending and potential fluctuations. To investigate these concerns, we study nominally stoichiometric Bi₂Se₃ using scanning tunnelling microscopy. Here we identify two distinct distributions of BiSe antisites that act as nanometer-scale sensors for the surface band-bending field. To confirm this, we examine bulk Cu-doped Bi₂Se₃ and demonstrate a significantly reduced surface band-bending field. In addition, we find that in the case of unintentionally doped Bi₂Se₃, lateral fluctuations of the Dirac point can be directly correlated with specific near-surface point defects, namely Se vacancies.

摘要

Bi₂Se₃ 最初作为拓扑物理的特别有前途的宿主出现。然而，在实际材料中，发现了几个问题，包括强表面能带弯曲和潜在的波动。为了研究这些问题，我们使用扫描隧道显微镜研究了名义上化学计量的 Bi₂Se₃。在这里，我们确定了两种不同的 BiSe 反位分布，它们作为纳米级表面能带弯曲场的传感器。为了证实这一点，我们研究了大块 Cu 掺杂的 Bi₂Se₃，并证明了表面能带弯曲场显著降低。此外，我们发现，在非故意掺杂的 Bi₂Se₃的情况下，狄拉克点的横向波动可以直接与特定的近表面点缺陷（即 Se 空位）相关联。