Symmetry Analysis of the Nonlinear Optical Response: New Magneto-Optical Effect in Second Harmonic Generation

TL;DR

This paper introduces a novel symmetry-based approach to use second harmonic generation (SHG) for detecting antiferromagnetism at surfaces and in thin films, enabling clear differentiation of magnetic states.

Contribution

It proposes a new nonlinear magneto-optical effect derived from symmetry analysis, allowing unambiguous identification of antiferromagnetic configurations even with unit-cell doubling.

Findings

Demonstrates polarization dependence of SHG on NiO surface

Proposes a symmetry-based method for magnetic state detection

Introduces a new nonlinear magneto-optical effect

Abstract

Using symmetry arguments we show how optical second harmonic generation (SHG) can be used to detect antiferromagnetism at surfaces and in thin films. Based on the group theoretical analysis of the nonlinear electric susceptibility we propose a new nonlinear magneto-optical effect, which allows even in the presence of unit-cell doubling for the unambiguous discri- mination of antiferromagnetic spin configurations from ferro- or paramagnetic ones. As an example for this effect we discuss the polarization dependence of SHG from the fcc (001) surface of NiO in some detail.