Approximate ab initio simulations of amorphous silicon and glassy chalcogenides

A classic problem of materials theory is to understand the properties of glasses and amorphous materials. Comprehension of disordered systems requires as an initial step atomistic models (coordinates of the atoms) that reproduce the known experimental features of the material. This includes structural (diffraction) information of course, but also higher-order correlations (as from new fluctuation electron microscopy techniques), dynamical information (inelastic neutron scattering, Raman and infrared measurements), electronic and optical information (photoelectron spectroscopy, optical spectra). Models proposed which are jointly in agreement with this array of measurements are likely to enable new insights and we name such models in this paper realistic. With such models available, theoretical analysis of properties beside structure becomes appropriate. The electronic and optical properties are commonly of most interest to applications. Such models also enable studies of localization, electron dynamics and other issues of fundamental appeal.  2002 Elsevier Science Ltd. All rights reserved.