Lateral transport of thermal capillary waves

TL;DR

This paper shows that thermal capillary waves at phase interfaces can exhibit lateral transport driven by asymmetric interfacial currents, revealing new mechanisms for nanoscale interfacial control.

Contribution

It introduces the concept that interfacial fluctuations can move laterally when driven by odd-function order parameter currents, supported by simulation and theoretical models.

Findings

Capillary waves can travel along interfaces with asymmetric currents.

Transport occurs only when the order parameter current is an odd function of position.

Discrete Gaussian interface models show similar transport phenomena.

Abstract

We demonstrate that collective motion of interfacial fluctuations can occur at the interface between two coexisting thermodynamic phases. Based on computer simulation results for driven diffusive Ising and Blume-Capel models, we conjecture that the thermal capillary waves at a planar interface travel along the interface if the lateral order parameter current j_op(y) is an odd function of the distance y from the interface and hence possesses opposite directions in the two phases. Such motion does not occur if j_op(y) is an even function of y. A discrete Gaussian interface model with effective dynamics exhibits similiar transport phenomena but with a simpler dispersion relation. These findings open up avenues for controlled interfacial transport on the nanoscale.