Interatomic correlations moments in graphene monolayer

This study investigated the interatomic correlation moments within a graphene monolayer using the correlative approach based on an unsymmetrized self-consistent field (CUSF) method. This analysis encompassed various approximations, such as the harmonic, quasi-harmonic, and weakly anharmonic models. Numerical evaluations for low temperatures were conducted employing the parametric interatomic potential specifically developed for graphene by Tewary and Yang. The findings revealed a notable reduction in the interatomic correlation moments with increased interatomic distance. Moreover, the correlations between the transverse atomic displacements were less pronounced than those between the longitudinal displacements. Additionally, the significance of anharmonicity was duly validated. Comparatively, the longitudinal atomic displacements in the graphene lattice exhibited a stronger correlation than the square and hexagonal lattices.