DFT-Based Tight-binding model of vdW bilayer & chi;3 and & beta;12 borophene

In this work, a tight-binding (TB) model with the Slater-Koster (SK) approximation is presented to describe the electronic properties of vdW bilayer & chi;3 and & beta;12 borophene with AA stack. This model is created by using four orbitals of S, Px, Py, and Pz for each boron atom. By fitting the results of the TB model and density functional theory (DFT) calculations using the least-squares method and the Levenberg-Marquardt nonlinear fitting algorithm, the optimal Hamiltonian and the overlap matrix are calculated. This TB model well describes energy bands around high-symmetry k-points, by considering three nearest neighbors in each layer and a nonorthogonal basis set.