paper

Time-dependent density-functional approach for exciton binding energies

arXiv:0903.0027 · doi:10.1103/PhysRevB.79.233201

Abstract

Optical processes in insulators and semiconductors, including excitonic effects, can be described in principle exactly using time-dependent density-functional theory (TDDFT). Starting from a linearization of the TDDFT semiconductor Bloch equations in a two-band model, we derive a simple formalism for calculating excitonic binding energies. This formalism leads to a generalization of the standard Wannier equation for excitons, featuring a nonlocal effective electron-hole interaction determined by long-range and dynamical exchange-correlation (XC) effects. We calculate excitonic binding energies in several direct-gap semiconductors, using exchange-only and model XC kernels.

4 pages, 1 figure

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