Ab initio calculation of linear and nonlinear optical properties of semiconductor structures

Abstract

The theoretical and numerical approaches are discussed for ab initio calculations of optical properties. The density functional theory (DFT) combined with the local-density approximation (LDA) allows the calculation of the geometry of crystalline solids and their surfaces with a precision of about one percent. The DFT-LDA band structure and single-electron states therefore provide a reasonable starting point for the calculation of linear and nonlinear susceptibilities within the independent-particle approximation. However, this approach has to be improved by taking into account many-body interactions: self-energy effects, local-field corrections, and electron-hole attraction. Three types of optical spectra are studied: the frequency-dependent dielectric function, the second-harmonic generation, and surface reflectance anisotropy spectra. The systems considered are two-atomic semiconductors, their polytypes and their surfaces.