Influence of pressure on (001)GaAs surfaces.

Abstract

This paper presents results of band-structure calculations for uniaxially stressed (001) GaAs surfaces. We discuss results for both ideal surfaces and 2\ifmmode\times\else\texttimes\fi{}1 reconstructed surfaces. Corresponding bulk-energy bands are projected onto the first surface Brillouin zone. The influence of uniaxial force on both surface and bulk energy bands is then discussed. The one-dimensional pressure coefficient of the fundamental band gap is calculated and compared with the corresponding hydrostatic pressure coefficient. Ideal surface-state energy bands were found to be relatively insensitive to the applied uniaxial force compared with the bulk bands. However, for 2\ifmmode\times\else\texttimes\fi{}1 reconstructed surfaces, the surface energy bands are sensitive to the applied uniaxial force (compared with the bulk bands): this originates primarily from the stronger dependence of the surface conduction band on pressure compared with the surface valence band. The influence of uniaxial force on the total density of states for ideal and 2\ifmmode\times\else\texttimes\fi{}1 reconstructed surfaces is discussed.