Tunable Negative Poisson’s Ratio in Van der Waals Superlattice
Unit cell of (a) graphene and (b) -BN. (c) Wave function superposition of A and B atoms. (d) The length of orbital in each layer of G/-BN superlattice under different strains. Here, represents the distance between A and B atoms. Under the in-plane strain , the length of orbital is .