Electronic Structure of Diluted Semimagnetic Semiconductor (Cd,Co)Se

The electronic structure of a new semimagnetic semiconductor (Cd,Co)Se is studied by UPS and calculated by a tight-binding version of the disordered-local-moment theory. The theory accounts for the chemical disorder and for electron interactions within the Co 3d$\text{}^{7}$ shells. Both theory and experiment show Co 3d states deep in the valence band and also at the band edge. The last state seem to be responsible for unique properties of the Co-based semimagnetic semiconductors.