Hole Transport in Impurity Band and Valence Bands Studied in Moderately Doped GaAs:Mn Single Crystals

摘要

We report on simple experiment on temperature-dependent Hall effectmeasurements in GaMnAs single crystalline samples with Mn composition estimatedat 0.05-0.3 at.% which is slightly below the onset of ferromagnetism. Impurityband transport is visible for Mn compositions of ~0.3 at.% as a clear metallicbehaviour. The results show interesting situation that the Metal-Insulatortransition in GaAs:Mn occurs within the impurity band which is separated fromthe valence bands for Mn concentrations studied here. We also discuss on theequilibrium high temperature solubility limit of Mn in GaAs, unknown preciselyin the literature.