▎ 摘　　要

Twisted bilayer materials have attracted tremendous attention due to their unique and novel properties. In this work, we derive a thermodynamic model for twisted bilayer graphene (tBLG) within the framework of the classical statistical mechanics. The effect of interlayer twist is introduced by the Moire-dependent out-of-plane deformation, based on which the twist associated Helmholtz free energy is quantified. Furthermore, the configuration entropy, reflecting the number of micro-states in Moire unit-cells, is directly derived from both the Helmholtz free energy and the Boltzmann entropy equation with a clear physical interpretation. We show the configuration entropy of a tBLG relative to the AB-stacked bilayer graphene is proportional to the logarithmic function of the ratio of Moire period (a(m)) and the lattice constant (a), i.e., S-tBLG-S-AB=12k(B)ln(a(m)/a). Finally, based on the observation that the out-of-plane deformation follows the evolution of Moire patterns, a possible dissipation mechanism in the interlayer sliding of tBLG is discussed. This work provides a theoretical guidance for studying the Moire effect of incommensurate contact interfaces such as tribology.