Experimental observation of the Aubry transition in two-dimensional colloidal monolayers

TL;DR

This study experimentally and theoretically demonstrates the Aubry transition in a two-dimensional colloidal monolayer at room temperature, revealing a first-order transition with coexistence of pinned and unpinned regions, relevant for nanodevice design.

Contribution

First experimental observation of the Aubry transition in 2D at room temperature using colloidal monolayers, showing a first-order transition with coexistence regime.

Findings

Aubry transition occurs in 2D colloidal systems at room temperature.

The transition is first-order, unlike the continuous 1D case.

Coexistence of pinned and unpinned regions observed.

Abstract

The possibility to achieve entirely frictionless, i.e. superlubric, sliding between solids, holds enormous potential for the operation of mechanical devices. At small length scales, where mechanical contacts are well-defined, Aubry predicted a transition from a superlubric to a pinned state when the mechanical load is increased. Evidence for this intriguing Aubry transition (AT), which should occur in one dimension (1D) and at zero temperature, was recently obtained in few-atom chains. Here, we experimentally and theoretically demonstrate the occurrence of the AT in an extended two-dimensional (2D) system at room temperature using a colloidal monolayer on an optical lattice. Unlike the continuous nature of the AT in 1D, we observe a first-order transition in 2D leading to a coexistence regime of pinned and unpinned areas. Our data demonstrate that the original concept of Aubry does not only survive in 2D but is relevant for the design of nanoscopic machines and devices at ambient temperature.