We provide a simple and intuitive explanation for the interlayer sliding energy landscape
of metal dichalcogenides. On the basis
of the recently introduced registry index (RI) concept, we define a purely geometrical parameter that quantifies the degree
of interlayer commensurability in the layered phase
of molybdenum disulfide (
2H-MoS
2). A direct relation between the sliding energy landscape and the corresponding interlayer registry surface
of 2H-MoS
2 is discovered. A simple fit
of the
model parameters to capture the sliding energy landscape obtained at different
external loads enables the identification and isolation
of the prominent interlayer interactions dictating the interlayer sliding physics under different tribological scenarios. The success
of our method in capturing the results
of complex quantum mechanical
calculations along with its high computational efficiency marks the RI as a promising tool for studying the tribology
of complex nanoscale material interfaces in the wearless friction regime.
Keywords:
molybdenum disulfide; registry index; layered materials; nanoscale tribology; interlayer sliding; interlayer commensurability