Piezoelectricity in planar boron nitride via a geometric phase

TL;DR

This paper provides an analytical derivation of the electronic piezoelectric response in monolayer hexagonal boron nitride, confirming its magnitude and symmetry properties through theoretical methods aligned with prior ab-initio results.

Contribution

It introduces an entirely analytical approach to calculate the piezoelectric response in hBN based on strain-induced pseudomagnetic fields and Berry curvature, advancing theoretical understanding.

Findings

Analytical derivation matches previous ab-initio results.

Reproduces expected symmetry restrictions of hBN.

Confirms the magnitude of piezoelectric effect in hBN.

Abstract

Due to their low surface mass density, two-dimensional materials with a strong piezoelectric response are interesting for nanoelectromechanical systems with high force sensitivity. Unlike graphene, the two sublattices in a monolayer of hexagonal boron nitride (hBN) are occupied by different elements, which breaks inversion symmetry and allows for piezoelectricity. This has been confirmed with density functional theory calculations of the piezoelectric constant of hBN. Here, we formulate an entirely analytical derivation of the electronic contribution to the piezoelectric response in this system based on the concepts of strain-induced pseudomagnetic vector potential and the modern theory of polarization that relates the polar moment to the Berry curvature. Our findings agree with the symmetry restrictions expected for the hBN lattice and reproduce well the magnitude of the piezoelectric effect previously obtained ab-initio.