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arXiv · 0812.3681

Valley Degeneracies in (111) Silicon Quantum Wells

Neerav Kharche·Seongmin Kim·Timothy B. Boykin·Gerhard Klimeck
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Abstract

(111) Silicon quantum wells have been studied extensively, yet no convincing explanation exists for the experimentally observed breaking of 6 fold valley degeneracy into 2 and 4 fold degeneracies. Here, systematic sp3d5s* tight-binding and effective mass calculations are presented to show that a typical miscut modulates the energy levels which leads to breaking of 6 fold valley degeneracy into 2 lower and 4 raised valleys. An effective mass based valley-projection model is used to determine the directions of valley-minima in tight-binding calculations of large supercells. Tight-binding calculations are in better agreement with experiments compared to effective mass calculations.

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Neerav Kharche, Seongmin Kim, Timothy B. Boykin, Gerhard Klimeck. 2008-12-18. Valley Degeneracies in (111) Silicon Quantum Wells. https://doi.org/10.1063/1.3068499

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