Temperature Behavior of Plasma Reflection Spectra of (Bi2–xSbx)Te3 (0 < х < 1) Crystals in the Temperature Interval 80–300 K

Abstract

A decrease in the resonant frequency ω_р of plasma fluctuations of free charge carriers with increasing temperature observed in all Bi_2-xSb_x (0 < х < 1) crystals can be explained only partly by the increased polarization background ε_∞ of the crystal. An analysis of the experimental data allows us to state that the change of ω_р and of the electrical conductivity σ is also caused by the decrease of the ratio of the free carrier concentration to their effective mass r/m^* (by a factor of 1.47) whose value almost coincides with the anomalous increase in the Hall coefficient in the temperature interval from 80 to 300 K.