Effect of temperature and defects on the mechanical and electronic properties of stacked van der Waals materials: The example of boron carbo-nitride

We demonstrate how the temperature and defects affect the electronic and mechanical properties in van der Waals bound low-dimensional systems, with the example of monolayer boron carbonitride (BCN). Molecular dynamics simulation reveals that as a hetero-structure of h-BN and graphene, the C-C bond in the BCN is responsible for an improved full width at half maximum (FWHM) compared to graphene, which ensures the structural integrity of the BCN monolayer. Besides, consistent with graphene and h-BN, the in-plane lattice parameter of BCN shows thermal contraction over a wide range of temperatures and exhibits a system size dependence. Further, the density functional theory calculations show that electronic bandgap varies substantially (between 0.73 and 1.2 eV) with the presence of Stone-Wales defects whereas it possess metallic character with the presence of vacancy defects. In addition, a tensile test analysis reveals that the elastic modulus and Poisson’s ratio of monolayer BCN are anisotropic and decrease (increase) with the application of uniaxial tensile (compressive) strain which is beneficial for many technological applications.