Molecular dynamics simulation for heat transport in thin diamond nanowires

TL;DR

This study uses molecular dynamics simulations to analyze heat transport in diamond nanowires, revealing size-dependent thermal conductivity, strong anisotropy based on growth direction, and potential applications in thermoelectric devices.

Contribution

It provides new insights into the size and directional dependence of thermal conductivity in diamond nanowires through detailed molecular dynamics simulations.

Findings

Thermal conductivity decreases with nanowire narrowing.

Ultra-narrow DNW exhibits very low thermal conductivity (~2.0 W/m/K).

Thermal conductivity varies significantly with growth direction, being highest along [110].

Abstract

The phonon thermal conductivity in diamond nanowires (DNW) is studied by molecular dynamics simulation. It is found that the thermal conductivity in narrower DNW is lower and does not show obvious temperature dependence; a very small value (about 2.0 W/m/K) of thermal conductivity is observed in ultra-narrow DNW, which may be of potential applications in thermoelectric devices. These two phenomena are probably due to the dominant surface effect and phonon confinement effect in narrow DNW. Our simulation reveals a high anisotropy in the heat transport of DNW. Specifically, the thermal conductivity in DNW along [110] growth direction is about five times larger than that of [100] and [111] growth directions. The anisotropy is believed to root in the anisotropic group velocity for acoustic phonon modes in DNW along three different growth directions.