Thermal expansion in nanoresonators

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.

Thermal conductance of suspended nanoribbons: interplay between strain and interatomic potential nonlinearity

“…Many challenging technological applications arise on the use of nanowires and nanotubes as strain sensors by inducing the system into a thermally nonlinear vibrational regime [24,27]. Our model shows a complementary technological implication.…”

“…Our proposed atomistic model is a suitable approach to understand thermal transport in nanosytems mediated by acoustic phonons. Many challenging technological applications arise on the use of nanowires and nanotubes as strain sensors by inducing the system into a thermally nonlinear vibrational regime [24,27]. Our model shows a complementary technological implication.…”

“…In a previous work [24] it was shown that for a general case of particles moving in three directions and when an uniaxial tension is applied, the nonlinear α-β FPU potential can be expanded around the new equilibrium positions for small displacements. If i and j are the indices of two neighboring atoms in the x direction, the relative longitudinal and perpendicular displacements are defined as ∆ long = r i,j .x − a x and ∆ 2 ⊥ = (r i,j .ŷ) 2 + (r i,j .ẑ) 2 respectively.…”

“…In a previous work [24] it was shown that for a general case of particles moving in three directions and when an uniaxial tension is applied, the nonlinear α-β FPU potential can be expanded around the new equilibrium positions for small displacements.…”

Nonlinear fluctuating hydrodynamics with many conserved fields: The case of a three-dimensional anharmonic chain

“…In this context, we extend recent works on anomalous thermal transport in low dimensional systems [11,12] in the framework of the NLFHT to the case of stressed anharmonic chains with 3D motion. The theoretical results are checked by molecular dynamics simulations.…”