Anderson Localization in Ferromagnetic Semiconductors Due to Spin Disorder I. Narrow Conduction Band

Abstract

Theoretical investigation is made of the temperature induced metal‐insulator transition in doped ferromagnetic semiconductors, described by s‐d exchange model. The transition is a result of the mobility edge movement, the disorder being due to magnetic ions spin density fluctuations. The electrons are described in tight binding approximation. Using ideas and methods of Anderson localization theory simple formulas are obtained, which connect the mobility edge with shortrange order characteristics of the magnetic subsystem‐static spin correlators. The theory developed is applied to the description of the resistivity of CdCr₂Se₄. The theoretical results are in agreement with experiment in a wide temperature range.