Resolve the governing mechanisms of torsional motion at van der Waals interfaces

Resolve how interfacial strain and stress evolve during yielding at van der Waals interfaces and determine how torsional quantities such as torque relate to translational quantities such as shear stress and friction.

Background

The paper studies torsional and translational mechanics at homo- and heterogeneous van der Waals interfaces, focusing on graphite/graphite and h-BN/graphite mesas. Although prior work has demonstrated rotational dynamics, twistable devices, torsional responses, and rotational friction phenomena, the authors identify the underlying mechanics of torsional motion as unresolved. In particular, the unresolved issues concern the evolution of interfacial strain and stress during torsional yielding and the relationship between rotational observables, such as torque, and translational observables, such as shear stress and friction. The paper subsequently addresses these issues by combining torsional and sliding experiments with atomistic simulations, proposing an edge-dominated yielding mechanism; the broader mechanistic question is therefore framed explicitly as unresolved at the outset.