Correlation between Electrical Properties and Crystalline Environment in Pb_1−xSn_xTe Mixed Crystals

Abstract

The electrical resistivity, Hall coefficient, and X-band EPR spectra have been measured over the temperature range from 300 to 77 K in the Bridgman-grown Pb_1−xSn_xTe (0≤x≤1) mixed crystals doped with 0.01 wt.% Mn as a probe. In accordance with a variation of the band gap with composition x, the electrical properties vary between the respective values for the two component semiconductors, but their behaviors are characterized by two regions; a Pb-rich side for x<0.3 and a Sn-rich side for x>0.4. In this mixed system alloy scattering is ineffective. With increasing x the hyperfine structure constant A of Mn²⁺ in the EPR spectra decreases drastically up to x=0.3∼0.4 and remains constant at higher tin composion, showing a stronger chemical affinity of Mn²⁺ with Sn atoms than Pb atoms. Only a limited range 0.1<x<0.4 there appear small lines due to forbidden transitions. In conclusion, the change in the electrical quantities with x is closely related with that in the chemical bonding nature in Pb_1−xSn_xTe.