# Effects of ballistic transport on the thermal resistance and temperature profile in nanowires

## TL;DR

This paper studies how heat moves in nanowires, showing that temperature gradients differ from traditional predictions due to ballistic transport effects.

## Contribution

The study introduces a radiator model that accurately captures ballistic transport effects in nanowires longer than the phonon mean free path.

## Key findings

- Molecular dynamics and phonon Monte Carlo simulations show reduced temperature gradients in the middle of nanowires.
- The radiator model predicts discrete jumps at wire ends, matching the observed steep gradients near heat sources and sinks.
- For wires longer than the phonon mean free path, the radiator model effectively accounts for ballistic transport.

## Abstract

Effects of ballistic transport on the temperature profiles and thermal resistance in nanowires are studied. Computer simulations of nanowires between a heat source and a heat sink have shown that in the middle of such wires the temperature gradient is reduced compared to Fourier’s law with steep gradients close to the heat source and sink. In this work, results from molecular dynamics and phonon Monte Carlo simulations of the heat transport in nanowires are compared to a radiator model which predicts a reduced gradient with discrete jumps at the wire ends. The comparison shows that for wires longer than the typical mean free path of phonons the radiator model is able to account for ballistic transport effects. The steep gradients at the wire ends are then continuous manifestations of the discrete jumps in the model.