(De)localization of nonequilibrium electrons in Pb 1− xSn xTe(In) in high magnetic field

Abstract

We report on high-field ( H<38 T) magnetoresistance and Hall effect measurements of initially dielectric Pb 0.75Sn 0.25Te(In). The data taken at 4.2 K show a magnetoresistance increase in time (localization) for a relatively low concentration of nonequilibrium electrons n. For a higher level of photoexcitation the localization disappears, and the Hall effect measurements, on the contrary, reveal an increase of n with field. The localization is attributed to energy band modulation. The delocalization is discussed in terms of field-induced electron transitions between the metastable local and extended states.