Impurity band conduction in single crystals of p‐type GaSb

Abstract

AbstractMeasurements of the Hall coefficient, dc conductivity at low and moderate electric fields, and magnetoresistance are made on heavily doped and compensated GaSb single crystals from liquid helium to room temperature range. The electrical transport in the low temperature region up to about 50 K is found to be mainly due to impurity band conduction by thermally activated hopping. The population of carriers in the impurity band and valence band is calculated from the Hall effect and low field conductivity data. The values of the average hopping distance in the impurity band at various temperatures are calculated from the observed data on high field dc conductivity. The magnetoresistance in the cryogenic temperature range is found to be negative while for temperatures between 40 and 150 K the magnetoresistance though positive shows significant deviation from the square law behaviour. For temperatures above 150 K, ΔQ/Q is found to vary with magnetic field B in accordance with the square law (ΔQ/Q ∼ B2) which is the normal behaviour of free charge carriers.