Model dielectric function for semiconductors

Abstract

We present a model for the dielectric function of semiconductors. It has been tested successfully for\ud Si, Ge, GaAs, and ZnSe. In conjunction with the single plasmon-pole approximation it yields plasmonenergy\ud dispersions in fair agreement with experiments. It allows one, moreover, to deduce an analytical\ud expression for the Coulomb-hole part of the static self-energy operator

Dielectric anisotropy in the GW space–time method

“…So far all implementations employ a number of additional simplifications to reduce the computational cost. Some of these are motivated by physical considerations, such as plasmon-pole models [15] or model dielectric functions [16,17,18,19], while others appear as purely mathematical "tricks" to improve the numerical stability or efficiency. Often, the validity and usefulness of a specific approach depends on the physical system under consideration.…”

Dielectric tensor of monoclinic Ga2O3 single crystals in the spectral range 0.5–8.5 eV

“…For optical properties, the inclusion of excitonic effects, treated within the Bethe-Salpeter equation (BSE) 45,46 framework, is crucial in order to allow a reasonable comparison with experimental spectra. We use the standard implementation of GW and BSE of VASP which employs the full frequency-dependent dielectric function without any approximations like the plasmon pole approximation 49 or model dielectric functions 50 for the calculation of the screened Coulomb interaction W and standard static screening in the BSE case. 45 For both, the GW and BSE calculations, we have to limit the k-point sampling to a grid of 8 × 8 × 8 k points including the Brillouin zone center Γ point, due to the limitation of the computing capacity caused by the high number of unoccupied bands needed to achieve reasonable convergence 50 to solve the Bethe-Salpeter equation where the calculation of the ω-dependent polarizability can be considered as an initial-value problem.…”

Impact ionization in GaAs: A screened exchange density-functional approach

“…The interaction between valence and conduction electrons is modeled by a Coulomb potential screened through a q-dependent static model dielectric function 12 (q) which is particularly accurate for semiconductors. The interaction between conduction electrons is modeled through a Debye potential; 2 both the temperature T and the carrier density in the conduction band n 0 are taken into account through an inverse Debye screening length 9 given by ϭͱ4 n 0 e 2 /K B T, where K B is the Boltzmann constant.…”