Mapping the 3D surface potential in Bi2Se3

Chris Mann, University of Texas at Austin
Damien West, Rensselaer Polytechnic Institute
Ireneusz Miotkowski, Purdue University
Yong P. Chen, Birck Nanotechnology Center, Purdue University
Shengbai Zhang, Rensselaer Polytechnic Institute
Chih-Kang Shih, University of Texas at Austin

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 Bi-Se 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.

Discipline(s)

Nanoscience and Nanotechnology