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arXiv · 1512.05156

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

O. Vänskä·M. Ljungberg·P. Springer·D. Sánchez-Portal·M. Kira·S. W. Koch
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Abstract

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.

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O. Vänskä, M. Ljungberg, P. Springer, D. Sánchez-Portal, M. Kira, S. W. Koch. 2015-12-16. Hybrid cluster-expansion and density-functional-theory approach for optical absorption in TiO2. https://doi.org/10.1364/josab.33.00c123

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