High-throughput first-principles prediction of superlubricity at the interfaces of NbS2 based heterostructures

Abstract

Heterostructures composed of transition metal dichalcogenides (TMD) monolayers hold great promise in structural superlubricity. Recently, NbS₂ has been synthesized and its potential as the solid lubricant has been demonstrated. In this study, high-throughput first-principles calculations were conducted to investigate the friction behavior of four NbS₂ based heterostructures: NbS₂/TiS₂, NbS₂/MoS₂, NbS₂/NbSe₂, and NbS₂/MoSe₂ heterostructures, aiming to discover novel superlubricants. Among these, the sliding energy barrier and lateral shear strength of NbS₂/TiS₂ and NbS₂/MoS₂ heterostructures are the highest and lowest, respectively. The low bonding strength, differential charge density, and large in-plane stiffness of NbS₂/MoS₂ heterostructures result in lower frictional forces and friction coefficients under various normal loads. Furthermore, under the load of 1nN, the friction coefficient (0.0011) at the interface of NbS₂/MoS₂ heterostructure approaches the superlubricity threshold of 0.001, highlighting its superlubricity. Additionally, it has been proven that the Moiré superlattice formed by interlayer distortion can effectively reduce interlayer friction, and the sliding energy barrier of the rotating NbS₂/TiS₂ and NbS₂/MoS₂ heterostructures is reduced to about 1/100 and 1/500 of the initial heterostructure, respectively. These predictions underscore the potential of NbS₂/MoS₂ heterostructures as promising candidates for atomically thin solid lubricants.