Accurate Multiscale Simulation of Frictional Interfaces by Quantum Mechanics/Green’s Function Molecular Dynamics

Understanding frictional phenomena is a fascinating fundamentalproblem with huge potential impact on energy saving. Such an understandingrequires monitoring what happens at the sliding buried interface,which is almost inaccessible by experiments. Simulations representpowerful tools in this context, yet a methodological step forwardis needed to fully capture the multiscale nature of the frictionalphenomena. Here, we present a multiscale approach based on linked ab initio and Green's function molecular dynamics,which is above the state-of-the-art techniques used in computationaltribology as it allows for a realistic description of both the interfacialchemistry and energy dissipation due to bulk phonons in nonequilibriumconditions. By considering a technologically relevant system composedof two diamond surfaces with different degrees of passivation, weshow that the presented method can be used not only for monitoringin real-time tribolochemical phenomena such as the tribologicallyinduced surface graphitization and passivation effects but also forestimating realistic friction coefficients. This opens the way to in silico experiments of tribology to test materials toreduce friction prior to that in real labs.