Strong non-Arrhenius temperature dependence of the resistivity in the regime of traditional band transport

Abstract

When a strong, though non-Arrhenius temperature dependence of electrical resistivity is observed, one usually concludes that the underlying mechanism is variable-range hopping. Unexpectedly, such observations are also made for many semiconductor systems at elevated temperatures, where a variable-range hopping mechanism seems unlikely. A satisfactory explanation for this observation is still lacking up to now. The authors demonstrate that a non-Arrhenius resistivity behavior may also arise in a band transport picture by thermal activation of charge carriers from a reservoir into the transport-carrying band states, provided the energy distribution of reservoir states is sufficiently broadened or the density of band states exhibits tails.