Phonon dissipation in friction with commensurate–incommensurate transition between graphene membranes

Abstract

To examine phonon transport during the friction process of commensurate–incommensurate transition, the vibrational density of states of contact surfaces is calculated based on molecular dynamics simulations. The results indicate that, compared with the static state, the relative sliding of the contact surfaces causes a blue shift in the interfacial phonon spectrum in or close to commensurate contact, whereas the contrast of the phonon spectrum in incommensurate contact is almost indiscernible. Further findings suggest that the cause of friction can be attributed to the excitation of new in-plane acoustic modes, which provide the most efficient energy dissipation channels in the friction process. In addition, when the tip and the substrate are subjected to a same biaxial compressive/tensile strain, fewer new acoustic modes are excited than in the no strain case. Thus, the friction can be controlled by applying in-plane strain even in commensurate contact. The contribution of the excited acoustic modes to friction at various frequency bands is also calculated, which provides theoretical guidance for controlling friction by adjusting excitation phonon modes.

Nanoscale friction characteristics of layered-structure materials in dry and wet environments

“…However, in the case of homostructure 2D layers, it is difficult to maintain the incommensurate configurations between the stacking layers because of the inherent orientation commensurability of the lattices (Kabengele and Johnson, 2021). Nevertheless, it has been suggested that the commensurability of the graphene/graphene homostructure can be changed by applying a strain to the graphene layer (Dong et al, 2020). In light of the foregoing studies, it may be inferred that the superlubricity of 2D bilayers strongly depends on both the contact size and the relative misfit angle between the adjacent layers (Bai et al, 2022).…”

“…A dependence of the friction force on phonon transport has also been observed at the nanoscale (Torres et al, 2006;Wang et al, 2007;Prasad and Bhattacharya, 2017). In a study aimed to elucidate the contribution of excited acoustic modes on the friction of a graphene layer in the commensurate-incommensurate transition, it was found that the friction force due to a graphene tip sliding against a rigid graphene layer can be controlled by prestraining the graphene layer (Dong et al, 2020). Prestraining (either tensile or compressive) caused the excitation of fewer acoustic modes, resulting in less friction energy dissipation (Dong et al, 2020).…”

“…In a study aimed to elucidate the contribution of excited acoustic modes on the friction of a graphene layer in the commensurate-incommensurate transition, it was found that the friction force due to a graphene tip sliding against a rigid graphene layer can be controlled by prestraining the graphene layer (Dong et al, 2020). Prestraining (either tensile or compressive) caused the excitation of fewer acoustic modes, resulting in less friction energy dissipation (Dong et al, 2020). An atomic-scale friction study of semiconductor surfaces revealed significant differences in friction due to atom charge accumulation (Park et al, 2006).…”

Stiffness and Atomic-Scale Friction in Superlubricant MoS2 Bilayers

“…However, in a superlubricant situation, the external forces dissipate into the internal atomic motion, a process that requires full molecular dynamics (MD). Then, the most typical setup consists of attaching the slider to a moving support through harmonic springs and in monitoring the spring forces over the MD trajectories, typically obtained with empirical force fields. − …”

Stiffness and atomic-scale friction in superlubricant MoS$_2$ bilayers

“…However, in a superlubricant situation the external forces dissipate into the internal atomic motion, a process that requires a molecular dynamics (MD) approach. In this case the most typical setup consists in attaching the slider to a moving support through harmonic springs and in monitoring the spring forces over the MD trajectories [24][25][26]. Empirical force fields are usually employed in this approach.…”