Valley Degeneracies in (111) Silicon Quantum Wells

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.

4 pages, 3 figures, to appear in Applied Physics Letters

References in corpus (3)

• Electronic measurement and control of spin transport in Silicon
• Integer quantum Hall effect on a six valley hydrogen-passivated silicon (111) surface
• Transport properties of two-dimensional electron systems on silicon (111) surfaces

Cited by in corpus (5)

• Tight-binding analysis of the electronic structure of dilute bismide alloys of GaP and GaAs
• Temperature-dependent transport in a sixfold degenerate two-dimensional electron system on a H-Si(111) surface
• Valley degeneracy in biaxially strained aluminum arsenide quantum wells
• Quantum Hall valley Ferromagnets as a platform for topologically protected quantum memory
• Universal transport at Lifshitz metal-insulator transitions in two dimensions