Atomic-Scale Friction on Monovacancy-Defective Graphene and Single-Layer Molybdenum-Disulfide by Numerical Analysis

• Published in: Nanomaterials (Basel, Switzerland) Vol. 10; no. 1; p. 87
• Main Authors: Pang, Haosheng, Wang, Hongfa, Li, Minglin, Gao, Chenghui
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 02.01.2020; MDPI
• Subjects: Atomic structure; atomic-scale friction; Experiments; Friction; Graphene; Mathematical models; Microscopy; Molecular dynamics; Molybdenum; monovacancy-defective graphene and single-layer molybdenum-disulfide (slmos2); Numerical analysis; numerical simulations; Parameters; Point defects; prandtl–tomlinson (pt) model; schwoebel–ehrlich barrier; Simulation; Slip; Spring constant; Tribology; Two dimensional materials; Vacancies; atomic-scale friction; numerical simulations; Schwoebel–Ehrlich barrier; monovacancy-defective graphene and single-layer molybdenum-disulfide (SLMoS2); Prandtl–Tomlinson (PT) model
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10010087

Using numerical simulations, we study the atomic-scale frictional behaviors of monovacancy-defective graphene and single-layer molybdenum-disulfide (SLMoS ) based on the classical Prandtl-Tomlinson (PT) model with a modified interaction potential considering the Schwoebel-Ehrlich barrier. Due to the presence of a monovacancy defect on the surface, the frictional forces were significantly enhanced. The effects of the PT model parameters on the frictional properties of monovacancy-defective graphene and SLMoS were analyzed, and it showed that the spring constant of the pulling spring is the most influential parameter on the stick-slip motion in the vicinity of the vacancy defect. Besides, monovacancy-defective SLMoS is found to be more sensitive to the stick-slip motion at the vacancy defect site than monovacancy-defective graphene, which can be attributed to the complicated three-layer-sandwiched atomic structure of SLMoS . The result suggests that the soft tip with a small spring constant can be an ideal candidate for the observation of stick-slip behaviors of the monovacancy-defective surface. This study can fill the gap in atomic-scale friction experiments and molecular dynamics simulations of 2D materials with vacancy-related defects.