Non-linear optical susceptibilities, Raman efficiencies and electrooptic tensors from first-principles density functional perturbation theory

TL;DR

This paper presents a first-principles density functional perturbation theory approach to calculate non-linear optical susceptibilities, Raman efficiencies, and electrooptic tensors in periodic solids, with analysis of convergence and correction effects.

Contribution

It introduces a new method based on the 2n + 1 theorem for computing non-linear optical and electrooptic properties from first principles, including convergence and correction considerations.

Findings

Validated the method on simple cases and compared with existing techniques.

Analyzed convergence behavior with respect to k-point sampling.

Discussed the impact of scissors correction on properties.

Abstract

The non-linear response of infinite periodic solids to homogenous electric fields and collective atomic displacements is discussed in the framework of density functional perturbation theory. The approach is based on the 2n + 1 theorem applied to an electric-field-dependent energy functional. We report the expressions for the calculation of the non-linear optical susceptibilities, Raman scattering efficiencies and electrooptic coefficients. Different formulations of third-order energy derivatives are examined and their convergence with respect to the k-point sampling is discussed. We apply our method to a few simple cases and compare our results to those obtained with distinct techniques. Finally, we discuss the effect of a scissors correction on the EO coefficients and non-linear optical susceptibilities.