Diluted magnetic semiconductors: Issues and opportunities

Abstract

We review the crystallography, band structure, and optical, electrical, and magnetic properties of diluted magnetic semiconductors (DMS), with emphasis on ternary alloys of the type AII1−xMnxBVI (e.g., Hg1−xMnxTe). Considerable attention in the review is given to spectacular novel effects which arise from the selective enhancement of spin-dependent properties due to exchange interaction between the localized magnetic moments (Mn+2) and band electrons. We then identify the major issues currently facing the field of DMS, and we discuss the major opportunities which these materials hold in store, both in the area of further scientific discoveries and in technological applications. In particular, we stress the need for a systematic concerted effort in the area of controlling impurities and defects in DMS, and we argue that exchange interaction in these materials offers an additional tool for studies in this area. We then describe, as examples of important future opportunities, the emerging field of Fe-based DMS (e.g., Hg1−xFexSe), and the rapidly evolving area of DMS superlattices and heterostructures. In connection with the latter, we give special attention to the unique features arising from the exchange interaction in the quantum well situation in alternating DMS/non-DMS structures.