Bifurcation of nanoscale thermolubric friction behavior for sliding on MoS2
Bifurcation of nanoscale thermolubric friction behavior for sliding on MoS2
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DOI：
10.1103/physrevmaterials.5.083607
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发表时间：
2021-08-26
影响因子：
3.4
通讯作者：
Carpick, Robert W.
中科院分区：
文献类型：
--
作者：
Hasz, Kathryn R.;Vazirisereshk, Mohammad R.;Carpick, Robert W.
在超高真空条件下，在宽温度（150-450 K）和扫描速度（5 nm/s至500 μ m/s）范围内，原子力显微镜实验了纳米尖端与大块和单层二硫化钼之间的无磨损滑动。原子晶格的粘滑行为被一致地解决了。然而，可以看到行为的分歧，一些测量显示摩擦随着温度的升高而强烈减少，而另一些测量显示在名义上相同的条件下无热摩擦和低摩擦。热和非热行为之间的差异归因于势能表面波纹的变化，可能是由于痕量的吸附污染物。虽然给定温度下的速度依赖关系与原子尺度摩擦的热普朗特-汤姆林森模型一致，但温度依赖关系并非如此（当它存在时），其他现有模型也无法描述温度依赖关系。考虑到测量结果，我们讨论了这些模型的局限性。
We present atomic force microscopy experiments of wearless sliding between nanoscale tips and both bulk and monolayer MoS2 in ultrahigh vacuum across a wide range of temperatures (150-450 K) and scanning speeds (5 nm/s to 500 mu m/s). Atomic lattice stick-slip behavior is consistently resolved. However, a bifurcation of behavior is seen, with some measurements showing a strong decrease in friction with increasing temperature and others showing athermal and low friction under nominally identical conditions. The difference between thermal and athermal behavior is attributed to a change in the corrugation of the potential energy surface, possibly due to trace amounts of adsorbed contaminants. While the speed dependence at a given temperature is consistent with the thermal Prandtl-Tomlinson model for atomic-scale friction, that is not the case for the temperature dependence (when it is present), nor can the temperature dependence be described by other existing models. We discuss the limitations of these models considering the measured results.