Continuum theory for the piezoelectric response of chiral nanotubes under uniaxial and torsional stresses

TL;DR

This paper develops a continuum model to analyze the piezoelectric response of chiral nanotubes under uniaxial and torsional stresses, revealing unique effects like stretch-twist coupling and bound charge density.

Contribution

It introduces a novel continuum theory that accounts for chiral angle and aspect ratio, predicting physical effects not observed in bulk materials.

Findings

Strong stretch-twist coupling observed

Significant bound charge density predicted

Model applied to boron-nitride nanotubes

Abstract

We develop and solve a continuum theory for the piezoelectric response of nanotubes under applied uniaxial and torsional stresses. We find that the piezoelectric response is controlled by the chiral angle, the aspect ratio, and two dimensionless parameters specifying the ratio of the strengths of the electrostatic and elastic energies. The model is solved in two limiting cases and the solutions are discussed. These systems are found to have several unexpected physical effects not seen in conventional bulk systems, including a strong stretch-twist coupling and the development of a significant bound charge density in addition to a surface charge density. The model is applied to estimate the piezoelectric response of a boron-nitride nanotube under uniform tensile stress.