1201.5609 (P. Di Pietro et al.)

Optical conductivity of Bismuth-based topological insulator    [PDF]

P. Di Pietro, F. M. Vitucci, D. Nicoletti, L. Baldassarre, P. Calvani, R. Cava, Y. S. Hor, U. Schade, S. Lupi

The optical conductivity and the spectral weight (SW) of four topological
insulators with increasing chemical compensation (Bi2Se3, Bi2-xCaxSe3,
Bi2Se2Te, Bi2Te2Se) have been measured from 5 to 300 K and from sub-THz to
visible frequencies. The effect of compensation is clearly observed in the
infrared spectra, through the suppression of the Drude term and the appearance
of strong peaks in the THz range, that we assign to electronic transitions
among impurity states. In the most compensated sample (Bi2Te2Se), the
far-infrared SW is higher than the spectral weight associated with topological
states by nearly two orders of magnitude.

View original: http://arxiv.org/abs/1201.5609