Theory of ferromagnetic semiconductors

Abstract

AbstractBased upon ab initio electronic structure calculations by the Korringa–Kohn–Rostoker coherent‐potential approximation (KKR‐CPA) method within the local‐density approximation (LDA), we propose a unified physical picture of magnetism and an accurate calculation method of Curie temperature (T C) in dilute magnetic semiconductors (DMSs) in II–VI and III–V compound semiconductors. We also propose the unified physical picture of magnetism in the DMS, where ferromagnetic Zener's double‐exchange mechanism (or Zener's p–d exchange mechanism) caused by the partially occupied impurity band and anti‐ferromagnetic super‐exchange mechanism (or ferromagnetic super‐exchange mechanism) is competing to determine the magnetic states in the DMS. We propose that the three‐dimensional 3D Dairiseki‐phase and one‐dimensional 1D Konbu‐phase caused by spinodal nano‐decomposition are responsible for high‐T C phase in the inhomogeneous system. We propose the new methodology to go beyond LDA to describe the highly correlated electron system by taking into account the self‐interaction correction (SIC) to the LDA. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)