Magnetic-Field-Induced Mott Transition in Semiconductors

Abstract

The influence of an applied magnetic field on semiconductor impurity states is calculated, including the effects of screening of the impurity-ion potential by free carriers. When the screening is sufficiently great so that no bound states occur at zero field, they are introduced at some critical field. If the semiconductor is extrinsic, then the appearance of bound states at the critical field results in a Mott transition as the field is increased. Free carriers are entrapped at impurity sites and the electrical conductivity is markedly reduced as the magnetic field is increased beyond the critical value.