# Thermal resistance of grain boundaries in silicon nanowires by nonequilibrium molecular dynamics

## TL;DR

This study investigates how the thermal boundary resistance at grain boundaries in silicon nanowires varies with twist angle using nonequilibrium molecular dynamics simulations, revealing a dependence on mismatch angle and boundary structure.

## Contribution

It provides a systematic analysis of the twist angle dependence of Kapitza resistance in silicon nanowires, including effects of boundary coincidence and finite size considerations.

## Key findings

- Kapitza resistance increases with twist angle up to 40°
- Resistance varies little (~1.56 K m^2/GW) for larger angles, except near 90°
- Finite size effects are negligible for diameters >25 nm

## Abstract

The thermal boundary resistance (Kapitza resistance) of (001) twist grain boundaries in silicon nanowires depends on the mismatch angle. This dependence is systematically investigated by means of nonequilibrium molecular dynamics simulations. Grain boundary systems with and without coincidence site lattice are compared. The Kapitza resistance increases with twist angle up to 40{\deg}. For larger angles, it varies only little around 1.56 $\pm$ 0.05 K m^2/GW, except for a drop by 30% near the 90{\deg} {\Sigma} 1 grain boundary. Finite size effects due to the fixed outer boundary conditions of the nanowire are negligible for diameters larger than 25 nm.