Magneto-optical effects in Bi_(1-x)As_x with x = 0.01: Comparison with topological insulator Bi_(1-x)Sb_x with x = 0.20

摘要

In this work, we explore possible topological insulating state in bismuth doped with arsenic Bi_(1-x)As_x. Infrared and magnetooptical spectroscopy are employed to probe the electrodynamic response of Bi_(1-x)As_x with x = 0.01, as well as topological insulator Bi_(1-x)Sb_x with x = 0.20. The spectra are reported in magnetic fields up to 18 T, and at temperatures between 10 and 300 K. The results indicate strong sensitivity of optical properties to these external stimuli in both Bi_(1-x)As_x and Bi_(1-x)Sb_x, but also some differences introduced by arsenic doping. Most notably, the field dependence of cyclotron resonance in Bi_(1-x)As_x implies that it is due to bulk carriers, as opposed to surface carriers in Bi_(1-x)Sb_x.