Cryolubricity in Atomic Scale Friction on YBCO Surface

The unique capabilities of ultra high vacuum AFM have been used to characterize temperature dependent friction on YBCO surface. We observed a significant decrease of friction upon cooling of YBCO samples to low temperatures. Our observation indicates the crucial role of electronic and phononic mechanisms of friction in solids at low temperatures. We will discuss the possible mechanisms of cryolubricity in high temperature superconductors.