Origin of the unusually large band-gap bowing and the breakdown of the band-edge distribution rule in the SnxGe1−x alloys
نویسندگان
چکیده
The unusual nonlinear behaviors of the band gaps in SnxGe1−x alloys are investigated using first-principles calculations. We show that the large bowing of the direct band gap is induced by the disordering effect. Moreover, we calculated individual contribution of the band-edge states and found that the bowing of the conduction band edge is much larger than the bowing of the valence band edge, although the natural valenceband offset between Ge and Sn is larger than the natural conduction-band offset. The breakdown of the band-edge distribution rule is explained by the large lattice mismatch between Ge and Sn and the large deformation potential of the band-edge states.
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