2015/12/16 by O. Vänskä, Osmo Vänskä, M. Ljungberg +7
Engineering · Materials Science · Physics and Astronomy · #Ab initio #Ab initio quantum chemistry methods #Absorption (acoustics) #Atomic physics #Band gap #Chalcogenide Semiconductor Thin Films #Cluster (spacecraft) #Cluster expansion #Condensed matter physics #Coulomb #Coupled cluster #Density functional theory #Dipole #Discrete dipole approximation #Electronic and Structural Properties of Oxides #Exciton #Hybrid functional #Materials science #Molecular physics #Optics #Optoelectronics #Physics #Quadrupole #Quantum Dots Synthesis And Properties #Quantum mechanics #Semiconductor #cond-mat.mtrl-sci
paper · pdf · doi:10.1364/josab.33.00c123
14 pages, 4 figures
arxiv created 2015/12/16 · openalex publication_date 2016/05/24 · arxiv updated 2016/06/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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.