Nanoscale friction behavior of transition-metal dichalcogenides: Role of the chalcogenide

Document Type

Article

Publication Date

11-24-2020

Abstract

Despite extensive research on the tribological properties of MoS2, the frictional characteristics of other members of the transition-metal dichalcogenide (TMD) family have remained relatively unexplored. To understand the effect of the chalcogen on the tribological behavior of these materials and gain broader general insights into the factors controlling friction at the nanoscale, we compared the friction force behavior for a nanoscale single asperity sliding on MoS2, MoSe2, and MoTe2 in both bulk and monolayer forms through a combination of atomic force microscopy experiments and molecular dynamics simulations. Experiments and simulations showed that, under otherwise identical conditions, MoS2 has the highest friction among these materials and MoTe2 has the lowest. Simulations complemented by theoretical analysis based on the Prandtl-Tomlinson model revealed that the observed friction contrast between the TMDs was attributable to their lattice constants, which differed depending on the chalcogen. While the corrugation amplitudes of the energy landscapes are similar for all three materials, larger lattice constants permit the tip to slide more easily across correspondingly wider saddle points in the potential energy landscape. These results emphasize the critical role of the lattice constant, which can be the determining factor for frictional behavior at the nanoscale.

Identifier

85096295704 (Scopus)

Publication Title

ACS Nano

External Full Text Location

https://doi.org/10.1021/acsnano.0c07558

e-ISSN

1936086X

ISSN

19360851

PubMed ID

33090766

First Page

16013

Last Page

16021

Issue

11

Volume

14

Grant

ACI-1548562

Fund Ref

National Science Foundation

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