Topological surface phonons modulate thermal transport in semiconductor thin films

TL;DR

This study reveals that topological surface phonons significantly influence thermal transport in semiconductor thin films, contributing over 30% to thermal conductivity at nanoscale dimensions and can be modulated by temperature and strain.

Contribution

It provides the first quantitative analysis of how topological surface phonons affect nanoscale thermal transport in semiconductors.

Findings

Topological surface phonons contribute over 30% to thermal conductivity in thin films.

Their contribution can reach up to 82 W/m-K at 300 K.

Temperature and biaxial strain effectively modulate this contribution.

Abstract

While phonon topology in crystalline solids has been extensively studied, its influence on thermal transport-especially in nanostructures-remains elusive. Here, by combining first-principles-based machine learning potentials with the phonon Boltzmann transport equation and molecular dynamics simulations, we systematically investigate the role of topological surface phonons in the in-plane thermal transport of semiconductor thin films (Si, 4H -SiC, and c-BN). These topological surface phonons, originating from nontrivial acoustic phonon nodal lines, not only serve as key scattering channels for dominant acoustic phonons but also contribute substantially to the overall thermal conductivity. Remarkably, for these thin semiconductor films below 10 nm this contribution can be as large as over 30% of the in-plane thermal conductivity at 300 K, and the largest absolute contribution can reach 82 W/m-K, highlighting their significant role in nanoscale thermal transport in semiconductors. Furthermore, we demonstrate that both temperature and biaxial strain provide effective means to modulate this contribution. Our work establishes a direct link between topological surface phonons and nanoscale thermal transport, offering the first quantitative assessment of their role and paving the way for topology-enabled thermal management in semiconductors.