Higher harmonics in Mott-Hubbard insulators as sensors

TL;DR

This paper demonstrates that higher harmonics generated in Mott-Hubbard insulators under oscillating electric fields can serve as sensitive probes of their spin order, microscopic hopping pathways, and the applied field, using strong-coupling perturbation theory.

Contribution

It provides analytical expressions linking higher-harmonic currents to microscopic properties of Mott insulators, highlighting their potential as sensors.

Findings

Higher harmonics encode information about spin order.

Higher harmonics reveal microscopic hopping pathways.

Higher harmonics can detect properties of the applied electric field.

Abstract

Using strong-coupling time-dependent perturbation theory, we study the response of Mott and charge-transfer insulators to an oscillating electric field. We derive analytical expressions for the resulting higher-harmonic currents and show that they encode information about spin order and microscopic hopping pathways. The results demonstrate that higher harmonics can serve as probes of correlated materials and as sensors of the applied driving field.