Constructing Anisotropic Single-Dirac-Cones in Bi1–xSbx Thin Films

Shuang Tang*† and Mildred S. Dresselhaus*‡

^† Department of Materials Science and Engineering,Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States

^‡ Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States

Nano Lett., Article ASAP

DOI: 10.1021/nl300064d

Publication Date (Web): March 20, 2012

Copyright © 2012 American Chemical Society

The electronic band structures of Bi_1–xSb_x thin films can be varied as a function of temperature, pressure, stoichiometry, film thickness, and growth orientation. We here show how different anisotropic single-Dirac-cones can be constructed in a Bi_1–xSb_x thin film for different applications or research purposes. For predicting anisotropic single-Dirac-cones, we have developed an iterative-two-dimensional-two-band model to get a consistent inverse-effective-mass-tensor and band gap, which can be used in a general two-dimensional system that has a nonparabolic dispersion relation as in the Bi_1–xSb_x thin film system.