Rohin Sharna
Kathmandu University, Nepal
Title: Electronic structure calculation of graphene by formulating a relativistic tight-binding approximation model
Biography
Biography: Rohin Sharna
Abstract
A non-perturbative relativistic Tight-Binding (TB) approximation method applicable to crystalline material immersed in a magnetic field was developed in 2015. To apply this method to any material in a magnetic field, the electronic structure of the material in absence of the magnetic field must be calculated. In this study, we present the relativistic TB approximation method for graphene in a zero magnetic field. The Hamiltonian and overlap matrix is constructed considering the nearest neighbouring atomic interactions between the s and p valence orbitals, where the relativistic hopping and overlap integrals are calculated using the relativistic version of the Slater-Koster table. The method of constructing the Hamiltonian and overlap matrix and the resulting energy-band structure of graphene in the first Brillouin zone is presented in this paper. It is found that there is an appearance of a small band-gap at the k points (also known as the spin-orbit gap) due to the relativistic effect, whose magnitude is 25 $mu$eV.