Magnetoplasma-Reflectivity of Pb1-XGeXTe

Abstract

Pb1-XGeXTe exhibits a structural phase transition from the cubic NaCl(Oh) to the rhombohedral As-like structure (C3v) at low lattice temperatures [1]. The transition temperature TC is a steep function of the Ge content. The infrared active mode of the cubic structure is split into an A1-mode and a double degenerate E-mode. These modes are both infrared and Raman active. A1 is observable for the polarization ^→E‖ c-axis [2,3]. In the cubic phase, electrons or holes are located in four equivalent L-valleys. Below TC, there are three equivalent L-valleys, and along the direction of the c-axis a T-valley.