Abstract
We show that at dilute Sn concentrations , the composition dependence of the direct band gap and spin-orbit splitting energies of can be described by a valence band anticrossing model. Hybridization of the extended and localized -like states of the Ge host matrix and the Sn minority atoms, respectively, leads to a restructuring of the valence band into and subbands. The notably large reduction in the band gap follows from an upward shift in the valence band edge by approximately per . These results demonstrate that like III-V and II-VI compound semiconductors, group IV elements may form highly mismatched alloys in which the band anticrossing phenomenon is responsible for their unique properties.
- Received 13 August 2007
DOI:https://doi.org/10.1103/PhysRevB.77.073202
©2008 American Physical Society