Friction behavior of monolayer molybdenum diselenide nanosheet under normal electric field

Fluctuation of Interfacial Electronic Properties Induces Friction Tuning under an Electric Field

“…However, in our simulation, the tuning effect still exists even in the cases of rigid sliding where the effect of the external field/current on the atomic configuration is eliminated, as shown in Figure S13, indicating that pure electronic behaviors could also affect friction. An electrostatic adhesion/repulsion force induced by the external field is also considered to be the reason for the friction tuning effect in some research. − , This is qualitatively correct according to our calculations: i.e., when the electrostatic force is an adhesive force, the sliding barrier will probably increase, and vice versa, as shown in Figure S14. However, from a quantitative point of view, in our experiment, the increases in adhesion force are less than 2% when the bias voltage is 500 mV, as shown in Figure S15, which cannot fully account for the more than 80% lateral force increase in the fcc region at this bias voltage (Figure e,f).…”

“…The tuning effects of electric field/current on electronic and electrostatic friction have also been investigated in previous studies. Electronic friction has been tuned by an electric field in noncontact friction experiments of Au/Au and Al/Au interfaces, , yet the magnitude was too small to account for the friction tuning in the contact friction. , Electrostatic force is generally considered as the reason for contact friction tuning. ,,− On one hand, an electrostatic force changes the adhesion force of the interface, which is equivalent to a change in the contact load. The electric-field- and current-induced adhesion and friction tuning of Si 3 N 4 /Si, Pt/MoS 2 , and Ir/MoSe 2 interfaces have been observed in AFM experiments.…”

“…Electronic friction has been tuned by an electric field in noncontact friction experiments of Au/Au and Al/Au interfaces, , yet the magnitude was too small to account for the friction tuning in the contact friction. , Electrostatic force is generally considered as the reason for contact friction tuning. ,,− On one hand, an electrostatic force changes the adhesion force of the interface, which is equivalent to a change in the contact load. The electric-field- and current-induced adhesion and friction tuning of Si 3 N 4 /Si, Pt/MoS 2 , and Ir/MoSe 2 interfaces have been observed in AFM experiments. On the other hand, in an experiment on a silicon p–n junction conducted by Park et al, although the adhesion force changed similarly with the bias voltage in both the p and n regions, a much larger friction increase was observed in the highly doped p region with greater electric current, indicating that the friction tuning cannot be simply attributed to the adhesion force .…”

Strong Substrate Strain Effects in Multilayered WS2 Revealed by High-Pressure Optical Measurements

“…This is to be expected for hydrostatic measurements since layer–substrate friction forces are several orders of magnitude higher than in bare tensile measurements. This is due to the fact that a strong normal force is present inside the hydrostatic chamber (the out-of-plane load per unit of area corresponds to the hydrostatic pressure F N = − P ) . Moreover, it is worth noting that the in-plane strain experienced by our samples is relatively small, around = −0.6% ( a being the lattice parameter and the lattice parameter of WS 2 at the highest pressure), compared to typical fully adhered tensile measurements, which are free of out-of-plane forces (i.e., F N = 0), around 1% .…”

Nanotribologia Em Grafeno E Outros Materiais Atomicamente Finos

“…F. Lavini e colaboradores mostra que para filmes policristalinos de MoS 2 , o atrito é maior para números ímpares de camadas, enquanto para números pares o efeito piezoelétrico não ocorre [90]. Já J. Peng e colaboradores conseguem uma modulação no coeficiente de atrito por aplicação de campo elétrico em cristais de MoSe 2 [91]; e F. He e colaboradores obtém uma redução de ∼ 30% no coeficiente de atrito pela aplicação de um potencial ao longo do plano para diferentes materiais 2D, como MoS 2 e h-BN [92]. As constantes piezoelétricas seguem uma tendência com a tabela periódica, sendo maior para compostos com átomos de Mo em relação à W, e também maior a medida em que se desce a coluna dos calcogenetos na tabela [93].…”