Piezo and flexoelectricity driven by inhomogeneous strain in 2D materials.

Electromechanical properties play an essential role in determining the physics of dielectric solids and their practical application. Popularly, electrostriction, and the piezoelectric effect were considered to be the two main electromechanical effects that couple an applied electric field to the strain and vice versa. The coupling between polarization and strain gradients is another electromechanical phenomenon, which can be observed by bending a material. This is known as flexoelectricity, which is present in a much wider variety of materials, including non-polar dielectrics and polymers, but is only significant at small length-scales, where high strain-gradients develop. In two dimensional (2D) materials, where large strain gradients are possible, these effects are expected to be strongly enhanced. Besides, the superior elastic properties and reduced lattice symmetry makes 2D materials promising for flexoelectricity. In this proposal, by using state of the art ab initio approaches, fundamental flexoelectric properties of a wide variety of 2D materials will be investigated. Subsequently, a multiscale modeling framework that captures the influence of internal-strain gradients on the electronic and optical properties will be developed. The work proposed here will not only provide a fundamental understanding of flexoelectricity in 2D materials but will also guide the discovery of new flexible electronics.

Keywords:2D MATERIALS

Disciplines:Dielectrics, piezoelectrics and ferroelectrics, Nanophysics and nanosystems, Structural and mechanical properties, Surfaces, interfaces, 2D materials, Computational materials science