Regulating Rolling and Sliding of Carbon Nanotubes on Graphite Through Doping and Charging

Nanostructures with controllable motion are indispensable to developing nanodevices. However, it still presents a fundamental challenge to effectively regulate the relative motion at the nanoscale, such as sliding and rolling. Since the potential energy surface that dictates the relative motion at the nanoscale is intrinsically determined by the underlying electron density, we employ doping and charging to regulate the sliding and rolling of carbon nanotubes (CNTs) on graphite (GRA). Herein, we focus on the single-walled (6, 6) CNTs on the fixed monolayer graphene, using density functional theory. We find that charging effectively enables N-doped CNTs to switch between sliding and rolling on GRA, whereas other dopants, such as B, Al, and P elements, generally cause the sliding preference for CNTs on GRA. Our findings uncover the difference and correlation between doping and charging in tuning the charge density as well as nanofriction. Therefore, our study is expected to provide some guide to the modulation of nano(electro) mechanical devices from the electronic point of view. Graphical Abstract