Defects in <i>h</i>-BN: computer simulation of size effects

Abstract

The influence of size effects on the properties of a hexagonal boron nitride (h-BN) monolayer containing CBVN, NBVN, and OBOBVN defects has been studied by first principles methods. These defects are potentially capable of generating single photons in quantum optics and quantum information devices. Size effects here mean the dependence of the studied model properties on the simulated fragment size of the 2D structure under periodic boundary conditions. Physically, this means that the properties of a monolayer depend on the distance between defects. This dependence allows us to judge how strongly the defects interact with each other and whether they interact at all. For technical applications, the characteristics of the band structure (band gap, spectrum and density of electron states induced by the defect in the band gap) and the atomic structure of the defect (defect formation energy, geometry in the equilibrium configuration), which form this band pattern, are important. In this work, these properties are studied by using the density functional theory with the basis of atom-like functions (SIESTA package) and plane waves (VASP package). The results obtained using both packages are consistent with each other. It has been established that the defects can be considered non-interacting, when the distance between them is ten unit cell parameters.