Electronic and optical properties of pure and modified diamondoids studied by many-body perturbation theory and time-dependent density functional theory

Tamás Demján, Márton Vörös, Maurizia Palummo, A. Gali

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Diamondoids are small diamond nanoparticles (NPs) that are built up from diamond cages. Unlike usual semiconductor NPs, their atomic structure is exactly known, thus they are ideal test-beds for benchmarking quantum chemical calculations. Their usage in spintronics and bioimaging applications requires a detailed knowledge of their electronic structure and optical properties. In this paper, we apply density functional theory (DFT) based methods to understand the electronic and optical properties of a few selected pure and modified diamondoids for which accurate experimental data exist. In particular, we use many-body perturbation theory methods, in the G0W0 and G0W0+BSE approximations, and time-dependent DFT in the adiabatic local density approximation. We find large quasiparticle gap corrections that can exceed thrice the DFT gap. The electron-hole binding energy can be as large as 4 eV but it is considerably smaller than the GW corrections and thus G0W0+BSE optical gaps are about 50% larger than the Kohn-Sham (KS) DFT gaps. We find significant differences between KS time-dependent DFT and GW+BSE optical spectra on the selected diamondoids. The calculated G0W0 quasiparticle levels agree well with the corresponding experimental vertical ionization energies. We show that nuclei dynamics in the ionization process can be significant and its contribution may reach about 0.5 eV in the adiabatic ionization energies.

Original languageEnglish
Article number064308
JournalThe Journal of Chemical Physics
Volume141
Issue number6
DOIs
Publication statusPublished - Aug 14 2014

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Electronic properties
Density functional theory
Optical properties
perturbation theory
density functional theory
optical properties
electronics
Diamond
Ionization potential
ionization
diamonds
Nanoparticles
Crystal atomic structure
Local density approximation
nanoparticles
Magnetoelectronics
test stands
Benchmarking
Binding energy
approximation

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Electronic and optical properties of pure and modified diamondoids studied by many-body perturbation theory and time-dependent density functional theory. / Demján, Tamás; Vörös, Márton; Palummo, Maurizia; Gali, A.

In: The Journal of Chemical Physics, Vol. 141, No. 6, 064308, 14.08.2014.

Research output: Contribution to journalArticle

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