Optical excitations of Si by time-dependent density-functional theory based on the exact-exchange Kohn-Sham band structure

We calculate the imaginary part of the frequency-dependent dielectric function of bulk silicon by applying time-dependent density-functional theory based on the exact-exchange (EXX) Kohn-Sham (KS) band structure and the adiabatic local-density approximation (ALDA) kernel. The position of the E2 abso...

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Bibliographic Details
Published in:arXiv.org 2002-02
Main Authors: Yong-Hoon, Kim, Staedele, Martin, Goerling, Andreas
Format: Article
Language:English
Subjects:
Band structure
Band structure of solids
Bulk density
Density functional theory
Exchanging
Kernels
Mathematical analysis
Particle interactions
Silicon
Time dependence
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Summary:We calculate the imaginary part of the frequency-dependent dielectric function of bulk silicon by applying time-dependent density-functional theory based on the exact-exchange (EXX) Kohn-Sham (KS) band structure and the adiabatic local-density approximation (ALDA) kernel. The position of the E2 absorption peak calculated with the EXX band structure at the independent-particle level is in excellent agreement with experiments, which demonstrates the good quality of EXX `KS quasiparticles'. The excitonic E1 peak that is missing at the independent-particle level remains absent if two-particle interaction effects are taken into account within the time-dependent LDA, demonstrating the incapability of the ALDA kernel to describe excitonic effects.
ISSN:2331-8422
DOI:10.48550/arxiv.0202214