Electronic Structure and Transport Properties of BiTe and BiSe Single Crystals.

The electrical resistivity and the Hall effect of topological insulator BiTe and BiSe single crystals were studied in the temperature range from 4.2 to 300 K and in magnetic fields up to 10 T. Theoretical calculations of the electronic structure of these compounds were carried out in density functional approach, taking into account spin-orbit coupling and crystal structure data for temperatures of 5, 50 and 300 K. A clear correlation was found between the density of electronic states at the Fermi level and the current carrier concentration. In the case of BiTe, the density of states at the Fermi level and the current carrier concentration increase with increasing temperature, from 0.296 states eV cell (5 K) to 0.307 states eV cell (300 K) and from 0.9 × 10 cm (5 K) to 2.6 × 10 cm (300 K), respectively. On the contrary, in the case of BiSe, the density of states decreases with increasing temperature, from 0.201 states eV cell (5 K) to 0.198 states eV cell (300 K), and, as a consequence, the charge carrier concentration also decreases from 2.94 × 10 cm (5 K) to 2.81 × 10 cm (300 K).