Excitonic effects on high-harmonic generation in Mott insulators

TL;DR

This study explores how excitonic effects influence high-harmonic generation in Mott insulators using advanced numerical methods, revealing enhanced HHG intensity near exciton energies and unique oscillatory dynamics.

Contribution

It provides the first detailed analysis of excitonic effects on HHG in Mott insulators through nonequilibrium simulations.

Findings

Enhanced HHG intensity around exciton energy.

Splitting and oscillation of the spectrum near exciton energy.

Distinct excitonic dynamics compared to free doublon-holon pairs.

Abstract

To study excitonic effects on high-harmonic generation (HHG) in Mott insulators, we investigate pumped nonequilibrium dynamics in the one-dimensional extended Hubbard model. By employing time-dependent calculations based on the exact diagonalization and infinite time-evolving block decimation methods, we find the strong enhancement of the HHG intensity around the exciton energy. The subcycle analysis in the sub-Mott-gap regime shows that the intensity region of the time-resolved spectrum around the exciton energy splits into two levels and oscillates following the driving electric field. This excitonic dynamics is qualitatively different from the dynamics of free doublon and holon but favorably contributes to HHG in the Mott insulator.