Ab initio calculations on oxygen vacancy defects in strained amorphous silica*

BH Zhou and FJ Zhang and X Liu and Y Song and X Zuo, CHINESE PHYSICS B, 29, 047103 (2020).

DOI: 10.1088/1674-1056/ab75db

The effects of uniaxial tensile strain on the structural and electronic properties of positively charged oxygen vacancy defects in amorphous silica (a-SiO2) are systematically investigated using ab-initio calculation based on density functional theory. Four types of positively charged oxygen vacancy defects, namely the dimer, unpuckered, and puckered four-fold (4 x), and puckered five-fold (5 x) configurations have been investigated. It is shown by the calculations that applying uniaxial tensile strain can lead to irreversible transitions of defect structures, which can be identified from the fluctuations of the curves of relative total energy versus strain. Driven by strain, a positively charged dimer configuration may relax into a puckered 5x configuration, and an unpuckered configuration may relax into either a puckered 4x configuration or a forward-oriented configuration. Accordingly, the Fermi contacts of the defects remarkably increase and the defect levels shift under strain. The Fermi contacts of the puckered configurations also increase under strain to the values close to that of E alpha '

Return to Publications page