The ideal (111), (110) and (100) surfaces of Si, Ge and GaAs; A comparison of their electronic structure

Abstract

In this paper we report all surface band structures and some layer densities of states for the ideal (111), (110) and (100) surfaces of Si, Ge and GaAs in comparison. The bulk materials are described by the best available empirical tight-binding Hamiltonians. The surface problem for semi-infinite solids is solved exactly using the Koster-Slater scattering-theoretic technique. The results for the different surfaces and the different materials are compared and characteristic properties stemming from particular surface geometries or varying ionicity are identified unambiguously. The calculations were carried out using first-nearest-neighbour as well as first- and second-nearest-neighbour bulk Hamiltonians. The sensitivity of the surface band structures with respect to the used bulk Hamiltonians is discussed, For some of the eleven different surfaces these are the first surface band structure calculations on the basis of a realistic tight binding bulk description.