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arXiv · 1410.8383

Band Anticrossing in Dilute Germanium Carbides Using Hybrid Functionals

Chad A. Stephenson·William A. O'Brien·Meng Qi·Michael Penninger·William Schneider·Mark A. Wistey
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Abstract

Dilute germanium carbides (Ge1-xCx) offer a direct bandgap for compact silicon photonics, but widely varying results have been reported. This work uses ab initio simulations with HSE06 hybrid functionals and spin-orbit coupling to study the Ge1-xCx band structure behavior in the absence of defects. Contrary to Vegard's law, the conduction band minimum at k=0 is consistently found to decrease with increasing C content, while L and X valleys change much more slowly. A vanishing bandgap was observed for all alloys with x>0.017. Conduction bands deviate from a constant-potential band anticrossing model except near the center of the Brillouin zone.

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Chad A. Stephenson, William A. O'Brien, Meng Qi, Michael Penninger, William Schneider, Mark A. Wistey. 2015-01-05. Band Anticrossing in Dilute Germanium Carbides Using Hybrid Functionals. https://doi.org/10.1007/s11664-015-4300-9

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