Hybrid cluster-expansion and density-functional-theory approach for optical absorption in TiO2
Autor: | Vänskä, O., Ljungberg, M., Springer, P., Sánchez-Portal, D., Kira, M., Koch, S. W. |
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Rok vydání: | 2015 |
Předmět: | |
Druh dokumentu: | Working Paper |
DOI: | 10.1364/JOSAB.33.00C123 |
Popis: | 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. Comment: 14 pages, 4 figures |
Databáze: | arXiv |
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