Elastic, electronic and thermodynamic properties of β-SiO2 doped by Ar: A first-principles investigation

Abstract

First-principles computations based on density functional theory (DFT) were used to investigate the doping formation energy, elastic constants, population analysis, and thermodynamic properties of the perfect and doped structures of β-SiO2. We find that the Ar interstitial doping structure is more easily formed but is mechanically unstable (C44 < 0). Derived mechanical parameters such as bulk modulus, shear modulus, and Young's modulus indicate that introducing the Ar atom reduces the β-SiO2 structure's ability to resist deformation and strain. Meanwhile, according to the results of the elastic anisotropy parameters (A1, A2, and A3 are not equal to 1), the perfect and Ar-substituted doping structures of β-SiO2 are anisotropic. The electronic properties of the structures were studied using population analysis, introducing the Ar atom increases the interatomic bonding length. Meanwhile, the O-Ar bond shows anti-bonding characteristics due to the negative population value of the bond. Furthermore, to investigate the stability of the doping structures, the binding energy of the structures was computed and the results indicate that the Ar-substituted O doping structure is more stable than the Ar-substituted Si doping structure.