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Ab-initio calculation of optical absorption in semiconductors: A density-matrix description

Ulrich Hohenester
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Abstract

We show how to describe Coulomb renormalization effects and dielectric screening in semiconductors and semiconductor nanostructures within a first-principles density-matrix description. Those dynamic variables and approximation schemes which are required for a proper description of dielectric screening are identified. It is shown that within the random-phase approximation the direct Coulomb interactions become screened, with static screening being a good approximation, whereas the electron-hole exchange interactions remain unscreened. Differences and similarities of our results with those obtained from a corresponding GW approximation and Bethe-Salpeter equation Green's function analysis are discussed.

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Ulrich Hohenester. 2001-08-21. Ab-initio calculation of optical absorption in semiconductors: A density-matrix description. https://doi.org/10.1103/physrevb.64.205305

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