Comment on "Piezoelectricity in planar boron nitride via a geometric phase"

TL;DR

This paper critiques previous analytical results on the piezoelectricity of 2D boron nitride, reconstructs a proper theoretical framework using Berry phase, and provides corrected expressions consistent with first-principles calculations.

Contribution

It introduces a corrected Berry phase-based method for calculating piezoelectric coefficients in 2D materials, addressing errors in prior analytical models.

Findings

Corrected analytical expressions align with first-principles results.

Reconstructed adiabatic process clarifies the theoretical foundation.

Established a general Berry phase formula for 2D piezoelectric crystals.

Abstract

Using the strain-dependent effective Hamiltonian and the geometric phase, Droth et al. [Phys. Rev. B 94, 075404 (2016)] obtain an analytical expression for the electronic contribution to the piezoelectricity of planar hexagonal boron nitride (h -BN). Their analytical results of piezoelectric constants for h -BN are invalid because of the mistakes in constructing the adiabatic process of the piezoelectricity. In this comment, we reconstruct a proper adiabatic process for piezoelectricity and formulate a general Berry phase expression for the piezoelectric coefficients of two-dimensional piezoelectric crystals by means of the modern theory of polarization. The corrected analytical results of the piezoelectric constants are in complete consistency with the first-principles calculations and hence manifest the validity and generality of the Berry phase expression of piezoelectric coefficients.