Bernasconi, L, Webster, R, Tomic, S and Harrison, NM 2012, 'Optical response of extended systems from time-dependent Hartree-Fock and time-dependent density-functional theory' , Journal of Physics: Conference Series, 367 , 012001.
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We describe a unified formulation of time-dependent Hartree-Fock (TD-HF) and time-dependent density-functional theory (TD-DFT) for the accurate and efficient calculation of the optical response of infinite (periodic) systems. The method is formulated within the linear-response approximation, but it can easily be extended to include higher-order response contributions, and, in TD-DFT, it can treat with comparable computational efficiency purely local, semi-local or fully non-local approximations for the ground-state exchange-correlation (XC) functional and for the response TD-DFT XC kernel in the adiabatic approximation. At variance with existing methods for computing excitation energies based on the diagonalisation of suitable coupling matrices, or on the inversion of a dielectric matrix, our approach exploits an iterative procedure similar to a standard self-consistent field calculation. This results in a particularly efficient treatment of the coupling of excitations at different k points in the Brillouin zone. As a consequence, our method has the potential to describe completely from first principles the optically induced formation of bound particle-hole pairs in wide classes of materials. This point is illustrated by computing the optical gaps of a series of representative bulk semiconductors, (non-spin polarised) oxides and ionic insulators.
|Schools:||Schools > School of Computing, Science and Engineering|
|Journal or Publication Title:||Journal of Physics: Conference Series|
|Depositing User:||Prof Stanko Tomic|
|Date Deposited:||06 Apr 2016 08:36|
|Last Modified:||06 Apr 2016 08:36|
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