Dynamical chiral symmetry breaking in sliding nanotubes

TL;DR

This paper reports the discovery of dynamical chiral symmetry breaking at the nanoscale in sliding nanotubes, where spontaneous angular momentum arises at specific velocities due to phonon interactions and nanofriction effects.

Contribution

It introduces a novel nanoscale symmetry breaking phenomenon driven by phonon dynamics and sliding friction, supported by simulations and theoretical analysis.

Findings

Spontaneous angular momentum appears at critical sliding velocities.

Symmetry breaking correlates with peaks in sliding friction.

Involves phonon interactions, Umklapp processes, and nanofriction effects.

Abstract

We discovered in simulations of sliding coaxial nanotubes an unanticipated example of dynamical symmetry breaking taking place at the nanoscale. While both nanotubes are perfectly left-right symmetric and nonchiral, a nonzero angular momentum of phonon origin appears spontaneously at a series of critical sliding velocities, in correspondence with large peaks of the sliding friction. The non-linear equations governing this phenomenon resemble the rotational instability of a forced string. However, several new elements, exquisitely "nano" appear here, with the crucial involvement of Umklapp and of sliding nanofriction.