High-harmonic generation in solids with and without topological edge states

TL;DR

This study explores how topological edge states in a one-dimensional structure dramatically influence high-harmonic generation, revealing potential for optical control of topological electronic systems.

Contribution

It demonstrates the significant impact of topological edge states on HHG yield using TDDFT, highlighting a giant effect up to fourteen orders of magnitude.

Findings

Harmonic yield varies greatly between topological phases.

Presence of edge states affects destructive interference in harmonic emission.

Topological effects can be exploited for optical control of electronic states.

Abstract

High-harmonic generation (HHG) in the two topological phases of a finite, one-dimensional, periodic structure is investigated using a self-consistent time-dependent density functional theory (TDDFT) approach. For harmonic photon energies smaller than the band gap, the harmonic yield is found to differ up to fourteen orders of magnitude for the two topological phases. This giant topological effect is explained by the degree of destructive interference in the harmonic emission of all valence-band (and edge-state) electrons, which strongly depends on whether topological edge states are present or not. The combination of strong-field laser physics with topological condensed matter opens up new possibilities to electronically control strong-field-based light or particle sources or---vice versa---to steer by all optical means topological electronics.