Study on the optical spectra of MgAl₂O₄ with oxygen vacancies

ABSTRACT

In this work, oxygen vacancies in MgAl₂O₄ crystal were investigated using the first-principles. The Heyd-Scuseria-Ernzerhof (HSE) was adopted to reproduce the experimental band gap. The finite-size correction scheme was applied to eliminate the unreal interaction between charged defects and their periodic images. Finally, taking into account of the electron-phonon coupling, we obtained the optical spectra of the F and F⁺ centres. The absorption peaks for the F and F⁺ centres are at 5.04 eV and 4.67 eV, respectively. Furthermore, we calculate the emission peak for the F centre is 3.28 eV. Comparing with the experimental results, the emission peak at 2.15 eV is related to the F⁺ centre.

KEYWORDS:

• Oxygen vacancies
• density functional theory
• finite-size correction
• hybrid density functional
• electron-phonon coupling
• optical spectra

Disclosure statement

No potential conflict of interest was reported by the authors.