Speaker
Dr
Irving Benjamin
(Czech Technical University in Prague)
Description
Low-dimensional materials have recently attracted immense interest due to their fascinating physical properties and potential for application in diverse fields such as (opto)electronics, energy harvesting and dry lubrication. Transition metal dichalcogenides (TMDs), of general form MX2 (M = Mo, W; X = S, Se, Te), are posited as being some of the best solid-state lubricants currently available. They exhibit a lamellar structure in which covalently-bonded MX2 layers are held together by weak van der Waals forces, which, together with very low ideal shear strengths (i.e., the maximum load applied parallel to the face of the material that can be resisted prior to the onset of sliding) render them suitable for use in the mitigation of friction. Our extensive density functional calculations highlight the dependence of important nanomechanical properties of TMDs on their chemical composition and bilayer orientation (sliding direction); in particular, our calculations underscore the intrinsic relationship between incommensurate layers and superlubricity.[2] Our latest calculations have focused on TMD-based van der Waals heterostructures (e.g. WS2 sliding on MoS2), with the aim of formalizing the relationship between fundamental quantum chemical parameters of the constituent elements and the nanomechanical properties of the material. Ultimately, we wish to improve the predictive capabilities of in silico methods during the material design process.
Summary
Density functional calculations performed using the Vienna Ab initio Simulation Package (VASP)[1] are used to deepen our understanding of the lubricity and associated nanomechanical properties of low-dimensional materials based on transition metal dichalcogenides.
References
[1] http://www.vasp.at/
[2] B. Irving, P. Nicolini and T. Polcar, Nanoscale, 2017, 9, 5597-5607
Primary author
Dr
Irving Benjamin
(Czech Technical University in Prague)
Co-authors
Dr
Paolo Nicolini
(Czech Technical University in Prague)
Prof.
Tomas Polcar
(University of Southampton)
