Thermal expansion in nanoresonators

TL;DR

This study uses molecular dynamics simulations to explore thermal expansion and frequency shifts in nanoresonators, revealing linear strain dependence and uniform expansion predictions applicable even at high temperatures.

Contribution

It introduces a model combining anharmonic atomic interactions and thermal reservoirs to analyze thermal expansion and frequency shifts in nanoresonators.

Findings

Thermal expansion is approximately uniform along the device.

Resonant frequency shifts linearly with applied strain.

Analytical harmonic approximation predicts uniform thermal expansion.

Abstract

Inspired by some recent experiments and numerical works related to nanoresonators, we perform classical molecular dynamics simulations to investigate the thermal expansion and the ability of the device to act as a strain sensor assisted by thermally-induced vibrations. The proposed model consists in a chain of atoms interacting anharmonically with both ends clamped to thermal reservoirs. We analyze the thermal expansion and resonant frequency shifts as a function of temperature and the applied strain. For the transversal modes the shift is approximately linear with strain. We also present analytical results from canonical calculations in the harmonic approximation showing that thermal expansion is uniform along the device. This prediction also works when the system operates in a nonlinear oscillation regime at moderate and high temperatures.