2019/08/13 by Weidong Yan, Yan, Weidong, Langquan Shui +5
Engineering · Materials Science · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Force Microscopy Techniques and Applications #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures
paper · pdf · doi:10.48550/arxiv.1908.04666
openalex publication_date 2019/08/13 · openalex created_date 2021/11/22 · openalex updated_date 2026/07/28
Twisted bilayer materials have attracted tremendous attention due to their unique and novel properties. Here, we derive a thermodynamic model for twisted bilayer graphene (tBLG) within the framework of the classical statistical mechanics, based on which, the configuration entropy reflecting the number of micro-status in moire unit-cells, is directly derived from the Helmholtz free energy with a clear physical interpretation. More importantly, we show the configuration entropy of tBLG relative to the AB-stacked bilayer graphene is proportional to the logarithmic function of the ratio of moire period and the atomic lattice constant, which we found dominates the Helmholtz free energy of tBLG and can well explain experimental observations in superlubric contacts. Our work provides a theoretical foundation for studying moire effect of incommensurate contact interfaces and could facilitate twisting based applications such as superlubricity.