First-principles prediction of half-metallic ferromagnetic semiconductors: V- and Cr-doped BeTe

From results of first-principles all-electron full-potential linearized augmented plane-wave calculations, a materials design of half-metallic ferromagnetic semiconductors based on V- and Cr-doped BeTe is proposed. Without the need of n- or p-type doping, the stability of the ferromagnetic spin configuration versus the antiferromagnetic state for V- and Cr-based systems is predicted, whereas the situation is reversed for Mn-doped BeTe ordered alloys. The calculated electronic and magnetic structures of transition-metal-doped BeTe shows that consistent with the integer value for the total magnetic moment, half metallicity is obtained for V- and Cr- doped structures, whereas the Mn-doped systems are semiconducting. A careful analysis of the spin density reveals the antiferromagnetic (ferromagnetic) coupling between the Cr and V (Mn) d states and the anion dangling-bond p states, which is believed to be responsible for the stabilization of the ferromagnetic (antiferromagnetic) phase. These ferromagnetic semiconductors offer a potential for semiconductor spintronic applications at room temperature; therefore, an experimental confirmation of our theoretical predictions is encouraged.