Mn-doped (formula presented) chalcopyrites: An ab initio study of ferromagnetic semiconductors

Abstract

Stimulated by our recent findings suggesting that the (formula presented) chalcopyrites could be a different class of ferromagnetic semiconductors, we performed first-principles calculations within density-functional theory and the generalized gradient approximation for Mn-doped (formula presented) Our calculations confirm the previous theoretical predictions on (formula presented) that the ferromagnetic spin configuration is strongly favored. Mn is found to be, as expected, both a source of localized magnetic moments and an acceptor; thus, our results seem to support the general idea that ferromagnetism is stabilized through a carrier-mediated interaction. For all the systems, we find a half-metallic character, consistent with the integer value of the total magnetic moment of (formula presented) per Mn atom. This is particularly important for spin-injection applications: in a significant energy range (i.e., about 0.5 eV in the dilute case) around the Fermi level relevant for spin injection, the holes will have a well-defined spin. A simple Heisenberg model to estimate the Curie temperature (formula presented) in ordered (formula presented) alloys gives (formula presented) therefore suggesting the possible importance of this class of ferromagnetic semiconductors for spintronic applications. © 2002 The American Physical Society.