Valley degeneracies in (111) silicon quantum wells

Author

• Neerav Kharche, Birck Nanotechnology Center, Network for Computational Nanotechnology, Purdue UniversityFollow
• Seongmin Kim, Birck Nanotechnology Center, Network for Computational Nanotechnology, Purdue UniversityFollow
• Timothy B. Boykin, Department of Electrical and Computer Engineering, University of Alabama at Huntsville
• Gerhard Klimeck, Birck Nanotechnology Center, Network for Computational Nanotechnology, Purdue UniversityFollow

Abstract

(111) silicon quantum wells have been studied extensively, yet no convincing explanation exists for the experimentally observed breaking of sixfold valley degeneracy into two- and fourfold degeneracies. Here, systematic sp(3)d(5)s(*) tight-binding and effective mass calculations are presented to show that a typical miscut modulates the energy levels, which leads to breaking of sixfold valley degeneracy into two lower and four 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.

Keywords

effective mass; elemental semiconductors; semiconductor quantum wells; silicon; tight-binding calculations

Citation

APPLIED PHYSICS LETTERS 94, 042101 (2009)

Date of this Version

1-26-2009

Recommended Citation

Kharche, Neerav; Kim, Seongmin; Boykin, Timothy B.; and Klimeck, Gerhard, "Valley degeneracies in (111) silicon quantum wells" (2009). Birck and NCN Publications. Paper 365.
https://docs.lib.purdue.edu/nanopub/365