Conduction-band structure of Bi2−xSbxSe3 mixed crystals by Shubnikov–de Haas and cyclotron resonance measurements in high magnetic fields

Abstract

The conduction-band structure of single crystals ${\mathrm{Bi}}_{2-x}{\mathrm{Sb}}_x{\mathrm{Se}}_3$ $(0\mathrm{}<~x<~0.52)$ was investigated in high magnetic fields by the Shubnikov–de Haas (SdH) effect (up to 40 T) and cyclotron resonance (up to 150 T). Signals from two conduction bands were detected in both experiments. The anisotropy of the Fermi surface and the effective masses for magnetic fields $B\parallel c$ and $B\perp c$ were determined for different x. It was found that the cyclotron masses for $B\parallel c$ in the upper and lower conduction bands do not depend on temperature or electron concentration. The temperature dependence of the resistivity, the Hall effect, and the Seebeck coefficient have been measured as functions of Sb concentration x. The free-electron concentration was found to be suppressed by the incorporation of Sb into ${\mathrm{Bi}}_2{\mathrm{Se}}_3$ crystals.