First-principles calculations of oxygen vacancy in CaO crystal
- PDF / 244,349 Bytes
- 6 Pages / 595.276 x 785.197 pts Page_size
- 75 Downloads / 287 Views
THE EUROPEAN PHYSICAL JOURNAL D
Regular Article
First-principles calculations of oxygen vacancy in CaO crystal Kaili Wu, Tingyu Liua , Ruxi Sun, Jiamei Song, and Chunyu Shi College of Science, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, P.R. China Received 25 May 2020 / Received in final form 15 August 2020 / Accepted 1 September 2020 Published online 13 October 2020 c EDP Sciences / Societ`
a Italiana di Fisica / Springer-Verlag GmbH Germany, part of Springer Nature, 2020 Abstract. We alleviate the band edge problem by adopting the advanced hybrid density functionals (with Alkauskas’s method). The finite-size correction scheme (FNV) is employed to align the defect formation energy. The defect formation energies of oxygen vacancies in CaO crystal with different charge states (0, +1, +2) are researched based on density functional theory. Firstly, we optimize all structures. Afterwards, the structures of defects with three charge states are analyzed. In the end, we give the accurate description of optical spectra for F and F + centers containing electron-phonon coupling. Based on our computing results, the absorption and luminescence spectra of the F center are peaked at 3.11 eV and 2.60 eV, the luminescence spectrum of the F + center is peaked at 3.84 eV, and the results are in agreement with the experimental conclusions that the results are 3.10 eV, 2.10 eV and 3.35 eV respectively. We can draw a conclusion that these methods are feasible for the computation of the optical spectra of point defects. Furthermore, their main advantage is that the computational expense and the computing requirements are within our computing power and they are far less than the computing requirements of the many body perturbation theory within the GW (Green’s function is multiplied by screened Coulomb potential) approach. In other words, our methods combine the advantages of various methods in the previous study to solve problems that other methods cannot settle. Thus, we can provide a reference to future’s studies on the point defects by employing these methods.
1 Introduction The calcium oxide (CaO) is a ubiquitous material with applications in a diverse range of areas such as medicine, plastics, rubber, papermaking, building construction, electronics, and microelectronics [1,2]. However, Certain performance of the material is influenced by the defects inside the material inevitably. For example, oxygen vacancy content can affect the performance of the crystal, which has raised people’s concern and interest for a long time. The method of producing the vacancies is thermochemical reduction (TCR), which is referred to as additive coloration, subtractive coloration, or electrolytic coloration [3]. Because of these defects, electronic structure and optical properties of the crystal are largely influenced. Thus, it is necessary to figure out their nature. Besides, we have known that the absorption band of the F centers is in the region of the F + emission about CaO crystal from the previous stu
Data Loading...
