Hybrid cluster-expansion and density-functionaltheory approach for optical absorption in TiO2

O. Vänskä, M. P. Ljungberg, P. Springer, D. Sánchez-Portal, M. Kira, Stephan W Koch

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2 Scopus citations


A combined approach of first-principles density-functional calculations and the systematic cluster-expansion scheme is presented. The dipole, quadrupole, and Coulomb matrix elements obtained from ab initio calculations are used as an input to the microscopic many-body theory of the excitonic optical response. To demonstrate the hybrid approach for a nontrivial semiconductor system, the near-bandgap excitonic optical absorption of rutile TiO2 is computed. Comparison with experiments yields strong evidence that the observed near-bandgap features are due to a dipole-forbidden but quadrupole-allowed 1s exciton state.

Original languageEnglish (US)
Pages (from-to)C123-C136
JournalJournal of the Optical Society of America B: Optical Physics
Issue number7
StatePublished - Jul 1 2016
Externally publishedYes


ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Atomic and Molecular Physics, and Optics

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