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

Abstract

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.

6 pages, 2 figures; contribution to "DFT 2001", Sep. 10-14, San Lorenzo de El Escorial, Spain; to be published in Int. J. Quantum. Chem

References in corpus (1)

• Exact Kohn-Sham exchange kernel for insulators and its long-wavelength behavior

Cited by in corpus (2)

• Excitonic effects in time-dependent density-functional theory: An analytically solvable model
• First-principles-derived effective mass approximation for the improved description of quantum nanostructures