Enhanced piezoelectricity and modified dielectric screening of 2-D group-IV monochalcogenides

TL;DR

This study uses first principles calculations to explore the lattice, dielectric, elastic, and piezoelectric properties of 2D group-IV monochalcogenides, revealing enhanced piezoelectricity and unique dielectric behavior in monolayers.

Contribution

It provides new insights into the dielectric and piezoelectric properties of 2D group-IV monochalcogenides, highlighting their potential for advanced nanoelectronic applications.

Findings

Monolayer permittivity depends on interlayer distance and exceeds 3D values.

Elastic properties are largely unaffected by reduced dimensionality.

Monolayers exhibit high piezoelectric constants, surpassing other 2D materials.

Abstract

We use first principles calculations to investigate the lattice properties of group-IV monochalcogenides. These include static dielectric permittivity, elastic and piezoelectric tensors. For the monolayer, it is found that the static permittivity, besides acquiring a dependence on the interlayer distance, is comparatively higher than in the 3D system. In contrast, it is found that elastic properties are little changed by the lower dimensionality. Poisson ratio relating in-plane deformations are close to zero, and the existence of a negative Poisson ratio is also predicted for the GeS compound. Finally, the monolayers shows piezoelectricity, with piezoelectric constants higher than that recently predicted to occur in other 2D-systems, as hexagonal BN and transition metal dichalcogenide monolayers.