Linear and Second-order Optical Response from First Principles

TL;DR

This paper develops a comprehensive first-principles formalism to calculate linear and second-order optical responses in semiconductors and insulators, including detailed analysis of spectra and interface effects.

Contribution

It introduces a full perturbation theory-based formalism for optical susceptibilities and applies it to a monolayer superlattice, highlighting interface selectivity in second-order responses.

Findings

Features in linear spectra originate from various band combinations.

Second-order spectra peaks are resonant with linear spectrum features.

Interface effects significantly influence second-order optical properties.

Abstract

We present a full formalism for the calculation of the linear and second-order optical response for semiconductors and insulators. The expressions for the optical susceptibilities are derived within perturbation theory. As a starting point a brief background of the single and many particle Hamiltonians and operators is provided. As an example we report calculations of the linear and nonlinear optical properties of the mono-layer InP/GaP (110) superlattice. The features in the linear optical spectra are identified to be coming from various band combinations. The main features in the second-order optical spectra are analyzed in terms of resonances of peaks in linear optical spectra. With the help of the strain corrected effective-medium-model the interface selectivity of the second-order optical properties is highlighted.