Quantum Flexoelectricity in Low Dimensional Systems

TL;DR

This paper introduces quantum flexoelectricity, where mechanical deformation in non-polar quantum systems induces dipole moments, with potential applications in nanoscale electromechanical devices.

Contribution

It proposes and demonstrates the concept of quantum flexoelectricity in low-dimensional carbon systems using density functional theory.

Findings

Flexoelectric coefficients are around 0.1 e.

Quantum flexoelectricity arises from curvature-induced dipoles.

Implications for nanoscale electromechanical devices.

Abstract

Symmetry breaking at surfaces and interfaces and the capability to support large strain gradients in nanoscale systems enable new forms of electromechanical coupling. Here we introduce the concept of quantum flexoelectricity, a phenomenon that is manifested when the mechanical deformation of non-polar quantum systems results in the emergence of net dipole moments and hence linear electromechanical coupling proportional to local curvature. The concept is illustrated in carbon systems, including polyacetylene and nano graphitic ribbons. Using density functional theory calculations for systems made of up to 400 atoms, we determine the flexoelectric coefficients to be of the order of ~ 0.1 e, in agreement with the prediction of linear theory. The implications of quantum flexoelectricity on electromechanical device applications, and physics of carbon based materials are discussed.