Interlayer friction behavior of molybdenum ditelluride with different structures

Zhang, Lína; Tan, Xinfeng; Jiao, Jianguo; Guo, Dan; Luo, Jianbin

doi:10.1007/s12274-023-5835-3

Cited by 2 publications

(4 citation statements)

References 42 publications

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“…For instance, the lateral force F lat is determined using F lat = −∇ E form ·s⃗, where s⃗ is a unit vector in the sliding direction. This approach is commonly used in the literature. , The lateral force is a result of the interfacial PES (molecule–substrate and molecule–molecule interactions). Its maximum value opposite the shear direction (i.e., when moving “up” an energy barrier) directly relates to the static friction coefficient.…”

Section: Resultsmentioning

confidence: 99%

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Impact of Static Distortion Waves on Superlubricity

Hörmann,

Cartus,

Hofmann

2023

ACS Omega

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Friction is a major source of energy loss in mechanical devices. This energy loss may be minimized by creating interfaces with extremely reduced friction, i.e., superlubricity. Conventional wisdom holds that incommensurate interface structures facilitate superlubricity. Accurately describing friction necessitates the precise modeling of the interface structure. This, in turn, requires the use of accurate first-principles electronic structure methods, especially when studying organic/metal interfaces, which are highly relevant due to their tunability and propensity to form incommensurate structures. However, the system size required to calculate incommensurate structures renders such calculations intractable. As a result, studies of incommensurate interfaces have been limited to very simple model systems or strongly simplified methodology. We overcome this limitation by developing a machine-learned interatomic potential that is able to determine energies and forces for structures containing thousands to tens of thousands of atoms with an accuracy comparable to conventional firstprinciples methods but at a fraction of the cost. Using this approach, we quantify the breakdown of superlubricity in incommensurate structures due to the formation of static distortion waves. Moreover, we extract design principles to engineer incommensurate interface systems where the formation of static distortion waves is suppressed, which facilitates low friction coefficients.

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Section: Resultsmentioning

confidence: 99%

“…This approach is commonly used in the literature. 71,72 The lateral force is a result of the interfacial PES (molecule− substrate and molecule−molecule interactions). Its maximum value opposite the shear direction (i.e., when moving "up" an energy barrier) directly relates to the static friction coefficient.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Impact of Static Distortion Waves on Superlubricity

Hörmann,

Cartus,

Hofmann

2023

ACS Omega

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“…As shown in Figure a, the lattice relaxation caused by the single Te atom vacancy defect had a wide range of effects (in the green dashed box), and the change in atomic position caused a change in the sliding potential energy, which affects the initial sliding position of the tip and the sliding energy barrier. In addition to the phonon dissipation part of the friction simulated by MD, the introduction of defects also caused electron transfer, as can be seen in Figure b, where the charge was transferred from the defect to the surrounding atoms after relaxation, and this inhomogeneous charge distribution also caused an increase in the frictional force. , …”

Section: Discussionmentioning

confidence: 96%

“…Interestingly, MoTe 2 can be stabilized at room temperature in both 2H and 1T′ phases and the energy difference between the two phases is very small. − The rich structural phases of MoTe 2 bring about a wealth of material properties. The interlayer frictional behavior of the 2H and 1T′ phases of MoTe 2 is quite different from its interfacial frictional behavior with silicon. , This means that it is possible to combine phase changes with friction modulation to achieve considerable changes in friction properties without introducing any other atoms. In addition, the presence of defects can promote the formation and growth of a new phase in the phase transition. , Cho et al found that the formation of Te vacancies is crucial for the phase transition of MoTe 2 from 2H to 1T′ phase, and the magnitude of defect density also affects the energy difference between the two structured phases.…”

Section: Introductionmentioning

confidence: 99%

Nonmonotonic Effects of Atomic Vacancy Defects on Friction

Zhang,

Chen,

Tan

et al. 2023

ACS Appl. Mater. Interfaces

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The presence of defects such as vacancies has a significant impact on the frictional properties of 2D materials that are excellent solid lubricants. In this study, we demonstrate that the nonmonotonic effect of Te vacancy defects on the friction of MoTe2 is related to the change in the maximum sliding energy barrier due to the variation in tip position. The experimental results of atomic force microscopy suggest that the friction shows an overall increasing trend with the increase in Te vacancy density, but this variation is nonmonotonic. Molecular dynamics simulations show that the increase in friction force with defect density can be attributed to the large and more sliding energy barriers that the tip has to overcome. Furthermore, the nonmonotonic variation of friction with defect density is dominated by the change of the maximum sliding potential barrier caused by the variation of tip position perpendicular to the sliding direction during the sliding process. Additionally, the uneven charge distribution due to charge transfer occurring at the defect also contributes to the increase in friction. This work shows the mechanism of the effect of Te vacancy defects on the friction of MoTe2, which provides guidance for the modulation of the frictional properties of solid lubricants.

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Interlayer friction behavior of molybdenum ditelluride with different structures

Cited by 2 publications

References 42 publications

Impact of Static Distortion Waves on Superlubricity

Impact of Static Distortion Waves on Superlubricity

Nonmonotonic Effects of Atomic Vacancy Defects on Friction

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