High-harmonic generation in the Rice-Mele model: Role of intraband current originating from interband transition

TL;DR

This paper investigates high-harmonic generation in the Rice-Mele model, emphasizing the importance of intraband current from interband transitions, especially near small gaps and half filling.

Contribution

It introduces the often-neglected intraband current from interband transitions into the theoretical framework of HHG in the Rice-Mele model.

Findings

Intraband current contribution is significant for small gaps.

The contribution is crucial near half filling.

Neglecting this leads to incomplete light-matter interaction models.

Abstract

We consider high-harmonic generation (HHG) in the Rice-Mele model to study the role of the intraband current originating from the change of the intraband dipole via interband transition. This contribution, which has been often neglected in previous works, is necessary for the consistent theoretical formulation of the light-matter coupling. We demonstrate that the contribution becomes crucial when the gap is smaller than or comparable to the excitation frequency and the system is close to the half filling.