Transversal flexoelectric coefficients for fifty select atomic monolayers from first principles

TL;DR

This study uses first-principles DFT calculations to determine transversal flexoelectric coefficients in fifty atomic monolayers, revealing linear behavior and material-dependent variations, with implications for nanoscale electromechanical applications.

Contribution

It provides a comprehensive first-principles analysis of flexoelectric coefficients across diverse 2D materials, highlighting electronic origins and material property dependencies.

Findings

Flexoelectric coefficients are linear with bending curvature.

TMTs exhibit coefficients up to five times larger than graphene.

Flexoelectric effect increases with monolayer thickness and atomic polarizability.

Abstract

We calculate transversal flexoelectric coefficients along the principal directions for fifty select atomic monolayers using ab initio Density Functional Theory (DFT). Specifically, considering representative materials from each of Groups IV, III-V, V monolayers, transition metal dichalcogenides (TMDs), Group III monochalcogenides, Group IV monochalcogenides, transition metal trichalcogenides (TMTs), and Group V chalcogenides, we perform symmetry-adapted DFT simulations to calculate the flexoelectric coefficients at practically relevant bending curvatures. We find that the materials demonstrate linear behavior and have similar coefficients along both principal directions, with values for TMTs being up to a factor of five larger than graphene. In addition, we find electronic origins for the flexoelectric effect, which increases with monolayer thickness, elastic modulus along bending direction, and sum of polarizability of constituent atoms.