Electron-scale origin of structural superlubricity

Abstract

First-principles computations are performed to study the phenomenon of structural superlubricity (SSL) relative to self-mismatched heterojunctions, rotating-mismatched homojunctions and curvature-mismatched coaxial double-walled nanotubes. It follows from the computations that the interfacial electron density fluctuation is responsible for all characteristics of SSL and can serve as predicting and describing them efficiently. This result further reveals that SSL comes from the fact that the incommensurable contact of two inert surfaces weakens their electronic interactions considerably. The model of SSL based on the electron redistribution a fortiori overcomes the limitations presented by the models of SSL based on the registry index (RI) or on the local pinning (LP).