Fig. 1: Tight-binding model of graphene lattice.
From: Machine learning sparse tight-binding parameters for defects
a Nearest-neighbor interactions in a hexagonal graphene lattice. The central gray atom has three first nearest neighbors (1NN, dark blue), 6 second-nearest neighbors (2NN, green), etc. b Interaction of a defect supercell with its periodic images (defect region highlighted in orange). The center cell itself is described by \({{{{\mathcal{H}}}}}^{(0,0)}\), the interactions to its neighboring cells by \({H}^{({\lambda }_{x},{\lambda }_{y})}\) --- for large supercells only the nearest-neighbor interactions between cells, i.e., λx, λy ∈ {−1, 0, 1} are non-zero.
