  The effects of a displacive structural phase transition on sliding friction
are in principle accessible to nanoscale tools such as the Atomic Force
Microscopy, yet they are still surprisingly unexplored. We present model
simulations demonstrating and clarifying the mechanism and potential impact of
these effects. A structural order parameter inside the material will yield a
contribution to stick-slip friction that is nonmonotonic as temperature crosses
the phase transition, peaking at the critical Tc where critical fluctuations
are strongest, and the sliding-induced order parameter local flips from one
value to another more numerous. Accordingly, the friction below Tc is larger
when the order parameter orientation is such that flips are more effectively
triggered by the slider. The observability of these effects and their use for
friction control are discussed, for future application to sliding on the
surface of and ferro- or antiferro-distortive materials.
