Narrowgap magnetic semiconductors Bruce W. Wessels , Northwestern University, DMR 0804479

1. We have been developing a model to explain why high Curie temperatures Tc have been observed in III-V compound semiconductor magnetic alloys with narrow band gaps. We propose that the transition metal manganese forms a shallow or resonant electronic level with the valence band. As a result there is strong hybridization between the p band and d band leading to carrier mediated ferromagnetism. InMnAs and InMnSb alloys show a high Tc The relationship of the Mn level to the band edge. The dashed line indicates the position of the calculated Mn acceptor level using a vacuum referred binding energy model Narrowgap magnetic semiconductorsBruce W. Wessels, Northwestern University, DMR 0804479 N. Parashar et al PRB 2010

2. New magnetic alloys are being developed for spin electronic applications The newest alloy is InMnSb with a Curie temperature above 400 K. An international collaboration has been established to determine mechanisms that lead to the high transition temperature Prof.Y. Matsuda of U. Tokyo uses Japan’s high field magnet facility in the study of our magnetic semiconductor alloys. Narrowgap magnetic semiconductorsBruce W. Wessels, Northwestern University, DMR 0804479 Y. Matsuda et al J. of Physics 2010