Ordering of the Nanoscale Step Morphology As a Mechanism for Droplet Self-Propulsion.
We establish a new mechanism for self-propelled motion of droplets, in which ordering of the nanoscale step morphology by sublimation beneath the droplets themselves acts to drive them perpendicular and up the surface steps. The mechanism is demonstrated and explored for Ga droplets on GaP(111)B, using several experimental techniques allowing studies of the structure and dynamics from micrometers