Self-trapped exciton configurations in Beryllium Oxide

5th International Congress on Energy Fluxes and Radiation Effects 2016

Botov, M.A.^1 ; Kuznetsov, A. Yu^2 ; Sobolev, A.B.^1

Dept. of High Mathematics, Ural Federal University, 19 Mira St., Yekaterinburg, Russia^1

Dept. of Experimental Physics, Ural Federal University, 19 Mira St., Yekaterinburg, Russia^2

关键词: Charge density distributions;    Defect configurations;    Electronic excitation;    Geometry relaxation;    Periodic boundary conditions;    Radiation technologies;    Self trapped excitons;    Self-trapped exciton;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/830/1/012158/pdf
DOI  :  10.1088/1742-6596/830/1/012158

来源: IOP

【 摘 要 】

The modern radiation technology, nuclear engineering, non-linear optics are associated with radiation-resistant optical material study. Evolution of electronic excitations in these materials is a complex multichannel process which currently has no integrated model. A special role belongs to the low-symmetry single crystals, such as beryllium oxide (BeO). We present theoretical results that advance our understanding of exciton-based channel of electronic excitations relaxation. The four possible self-trapped exciton (STE) configurations in beryllia single crystal have been investigated by using a quantum mechanical approach (Hartree-Fock and B3LYP HF-DFT hybrid functional, as implemented in the CRYSTAL09 code). B3LYP DFT functional with 30% of exact exchange was used (B3LYP30). All calculations were performed using periodic boundary conditions and full SC geometry relaxation. The lattice distortion and charge density distribution for considered defect configurations were obtained. STE-A1 luminescence energy was found to be 6.0 eV for HF and 6.5 eV for B3LYP30; STE-A2 luminescence energy was found to be 9.2 eV for HF and 7.8 eV for B3LYP30. STE-B1 luminescence energy was found to be 5.5 eV for HF, 6.2 eV for B3LYP30; STE-B2 luminescence energy was found to be 4.7 eV for HF.