R. Del Sole

Microscopic theory of optical properties of crystal surfaces

Abstract Light-propagation equations at crystal surfaces are solved in the long-wavelength limit, fully accounting for surface anisotropy, inhomogeneity and non-locality of the dielectric susceptibility tensor. Local-field and excitonic effects are also accounted in principle. Equations allowing calculation of internal and external reflectivity coefficients are given and used to analyze experimental data.

An efficient method for calculating quasiparticle energies in semiconductors

We present a method for the efficient calculation of the electronic structure of semiconductors within the GW approach. It approximately includes dynamical-screening and local-field effects, previously disregarded in simplified GW approaches, without increasing the computational effort. Such effects substantially affect the gap corrections. We find quasiparticle shifts in good agreement with the complete GW calculations or experiment for Si, AlAs, GaAs and ZnSe.

Strong excitons in novel two-dimensional crystals: Silicane and germanane

We show by first-principles calculations that, due to depressed screening and enhanced two-dimensional confinement, excitonic resonances with giant oscillator strength appear in hydrogenated Si and Ge layers, which qualitatively and quantitatively differ from those of graphane. Their large exciton binding energies and oscillator strengths make them promising for observation of novel physical effects and application in optoelectronic devices on the nanoscale.

AB INITIO OPTICAL PROPERTIES OF SI(100)

We compute the linear optical properties of different reconstructions of the clean and hydrogenated Si(100) surface within DFT-LDA, using norm-conserving pseudopotentials. The equilibrium atomic geometries of the surfaces, determined from self-consistent total-energy calculations within the Car-Parrinello scheme, strongly influence reflectance anisotropy spectra, showing differences between the

ANALYTICAL EXPRESSIONS FOR THE LOCAL-FIELD FACTOR G(Q) AND THE EXCHANGE-CORRELATION KERNEL KXC(R) OF THE HOMOGENEOUS ELECTRON GAS

p(2\ifmmode\times\else\texttimes\fi{}2)

Optical and electron energy-loss spectra of Si(111)2 × 1

and

Structural models of reconstructed Si(110) surface phases

c(4\ifmmode\times\else\texttimes\fi{}2)

Excitons in semiconductor confined systems

reconstructions. The differential reflectivity spectrum for the

Optical properties of germanium nanocrystals

c(4\ifmmode\times\else\texttimes\fi{}2)

Ab initio study of reflectance anisotropy spectra of a submonolayer oxidized Si(100) surface

reconstruction shows a positive peak at