Average bond energy and deformation potentials: Application to SiGe heterointerfaces

Abstract

This paper reports a theoretical determination of the valence-band offsets (VBOs) at SiGe strained heterointerfaces under different strain conditions, in the framework of average bond energy theory (ABET) in conjunction with the deformation potential method, based on the ab initio pseudopotentials and linearized-muffin-tin orbitals (LMTO) band structure methods, independently. It is shown that the validity of ABET is independent of the specific band structure method. It is found that the average VBO is almost unaltered under different strain conditions, while, the VBO between the topmost valence-band states is sensitive to the strain condition (changes up to ∼0.5 eV). This sensitivity is due to the alteration in the valence-band structures induced by the uniaxial stress and its interaction with the spin-orbit splitting. Our results are in good agreement with the photoemission measurement. The accuracy of the present results is examined by self-consistent supercell calculations.