Effects ofdbands on semiconductorspHamiltonians

The effects of Mn d electrons on the appropriate description of band-edge states in II-VI diluted magnetic semiconductors (DMS) is examined. In the absence of a magnetic field, such states are reasonably described by an ‘‘effective’’ sp band k⋅p Hamiltonian with matrix elements which include the effects of sp-d hybridization. At k=0, the addition of a nonzero-spin polarization leads to an effective sp Hamiltonian with the same form as that of the usual mean-field exchange Hamiltonian for DMS. The consistency of the explicit relationships derived here between microscopic and effective parameters is demonstrated for the case of ${\mathrm{Cd}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Mn}}_{\mathrm{x}}$Te. Both the electron and light-hole effective masses in this system are predicted to increase because of sp-d hybridization.