Temperature dependent structural, electronic and optical properties of the Si(100) surface from first principles

Abstract

The results presented here were obtained using the local density approximation (LDA) to density functional theory (DFT), within the pseudo-potentials scheme. We present the results of the numerical simulations for the Si bulk and Si(100) surface; ab-initio molecular dynamics (AIMD) using the Car-Parrinello Molecular Dynamics formalism (CPMD) and Born-Oppenheimer Molecular Dynamics (BOMD), related vibrational states (surface phonons) by calculating the vibrational density of states (VDOS) using a harmonic and anharmonic approach, and the optical response of the Si bulk and Si(100) surface calculating the temperature dependent reflectance anisotropy (RA). The surface reconstruction and temperature stimulated dimer flip impacts the surface reconstruction dynamics, the surface band gap and the optical response. For the calculated optical response and phonon spectra real temperature dependent atomic motion has been incorporated into the numerical formalism explicitly. This allows us to calculate the above materials’ properties, and reach an agreement with experiment, at different temperatures.