Effect of vacancy defects in 2D vdW graphene/h-BN heterostructure: First-principles study

Graphene (G) and hexagonal Boron Nitride (h-BN) are structurally similar materials but have very different electronic and magnetic properties. Heterostructures formed by the combination of these materials are of great research interest. To assess the role played by the crystalline defects in such heterostructures is also of crucial importance owing to their novel properties. In the present work, we study the structural, electronic, and magnetic properties of the G/h-BN heterostructure and the different possible point defects of B and N atoms in it by using first-principles calculations based on the spin-polarized density functional theory (DFT) method within the van der Waals correction DFT-D2 approach. The structural analysis of these systems shows that they are stable two dimensional van der Waals heterostructure materials. Band structure calculations of these materials reveal their semimetallic nature. On the basis of density of states and partial density of states calculations, the defective systems are magnetic materials. The magnetic moment obtained in these defective systems is due to the unpaired up-spin and down-spin states in the orbitals of C, B, and N atoms created by the vacancy defects. On the other hand, the G/h-BN heterostructure has an approving condition for ferromagnetism due to the presence of flat bands in the neighborhood of the Fermi energy.