Universality of phonon transport in surface-roughness dominated nanowires

TL;DR

This paper demonstrates a universal behavior in the thermal conductivity of surface-rough nanowires, showing it depends on a specific combination of parameters and follows a d^{1/2} scaling with diameter.

Contribution

The study introduces a universal regime for phonon transport in nanowires, linking thermal conductivity to a single parameter combination despite multiple surface characteristics.

Findings

Thermal conductivity follows a universal function of combined parameters.

Numerical simulations confirm the d^{1/2} dependence of conductivity on diameter.

Universal regime applies across various surface roughness conditions.

Abstract

We analyze, both theoretically and numerically, the temperature dependent thermal conductivity \k{appa} of two-dimensional nanowires with surface roughness. Although each sample is characterized by three independent parameters - the diameter (width) of the wire, the correlation length and strength of the surface corrugation - our theory predicts that there exists a universal regime where \k{appa} is a function of a single combination of all three model parameters. Numerical simulations of propagation of acoustic phonons across thin wires confirm this universality and predict a d 1/2 dependence of \k{appa} on the diameter d.