Effect of hydrostatic pressure on transport in the topological insulator Bi${}_2$Te${}_2$Se

Abstract

The Hall coefficient $R_H$ and resistivity $\rho$ of the topological insulator Bi${}_2$Te${}_2$Se display a number of puzzling features vs. temperature $T$. We propose a model that describes well the non-monotonic variation of $R_H(T)$. A key feature of the model is a chemical potential that is weakly $T$-dependent. From the fit to the model, we infer a "transport" gap ${\Delta }_T$ of 50 mV. We find that hydrostatic pressure $P$ (0-27 kbar) has a pronounced effect on both $R_H$ and $\rho$. We show that these changes arise from decreases in both ${\Delta }_T$ and the hole effective mass under pressure.

arXiv comment4 pages, 4 figs., 1 table