Giant electro-optic and elasto-optic effects in ferroelectric NbOI${}_2$

Abstract

First-principles calculations are performed to investigate the electro-optic (EO) and elasto-optic effects of the three-dimensional (bulk) and two-dimensional (monolayer) ferroelectric NbOI${}_2$. Remarkably large linear EO and elasto-optic coefficients are discovered in both systems, when under stress-free conditions. We further found that the EO responses of bulk and monolayer NbOI${}_2$ can be further enhanced with epitaxial strain, because of a strain-driven ferroelectric-to-paraelectric transition that originates from the softening of some polar optical modes. Our findings thus point out that NbOI${}_2$, as well as other niobium oxide dihalides are highly promising for paving the way for potentially efficient nonlinear optical device applications.

6 pages, 3 figures

References in corpus (2)

• Data-driven discovery of high performance layered van der Waals piezoelectric NbOI2
• Electro-optic properties from ab initio calculations in two-dimensional materials