Ab initio optoelectronic properties of silicon nanoparticles: Excitation energies, sum rules, and Tamm-Dancoff approximation

Dario Rocca, Márton Vörös, A. Gali, Giulia Galli

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We present an ab initio study of the excited state properties of silicon nanoparticles (NPs) with diameters of 1.2 and 1.6 nm. Quasiparticle corrections were computed within the G0W0 approximation. The absorption spectra were computed by time-dependent density functional theory (TDDFT) using the adiabatic PBE approximation, and by solving the Bethe-Salpeter equation (BSE). In our calculations, we used recently developed methods that avoid the explicit inversion of the dielectric matrix and summations over empty electronic states. We found that a scissor operator reliably describes quasiparticle corrections for states in the low energy part of the spectra. Our results also showed good agreement between the positions of the absorption peaks obtained using TDDFT and the BSE in the low part of the spectra, although the peak intensities differ. We discuss the effect of the Tamm-Dancoff approximation on the optical properties of the NPs and present a quantitative analysis in terms of sum rules. In the case of the BSE we found that, even in the absence of the Tamm-Dancoff approximation, the f-sum rule is not fully satisfied due to an inconsistency between the approximations used for the BSE kernel and for the quasiparticle Hamiltonian.

Original languageEnglish
Pages (from-to)3290-3298
Number of pages9
JournalJournal of Chemical Theory and Computation
Volume10
Issue number8
DOIs
Publication statusPublished - Aug 12 2014

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Excitation energy
Silicon
Bethe-Salpeter equation
Optoelectronic devices
sum rules
Density functional theory
Nanoparticles
Hamiltonians
nanoparticles
Electronic states
silicon
approximation
Excited states
excitation
Absorption spectra
Optical properties
energy
density functional theory
Chemical analysis
quantitative analysis

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Computer Science Applications

Cite this

Ab initio optoelectronic properties of silicon nanoparticles : Excitation energies, sum rules, and Tamm-Dancoff approximation. / Rocca, Dario; Vörös, Márton; Gali, A.; Galli, Giulia.

In: Journal of Chemical Theory and Computation, Vol. 10, No. 8, 12.08.2014, p. 3290-3298.

Research output: Contribution to journalArticle

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