Interband and intraband transitions, as well as charge mobility in driven two-band model with electron phonon coupling

TL;DR

This paper explores how external periodic drivings affect interband and intraband transitions and charge mobility in a two-band model with electron-phonon coupling, using novel Floquet-based simulation methods.

Contribution

It introduces Floquet surface hopping and Floquet mean field methods to simulate driven electronic dynamics in a two-band system with electron-phonon interactions.

Findings

Periodic drivings enhance interband transitions.

Periodic drivings suppress intraband transitions.

Charge mobility is reduced by external periodic drivings.

Abstract

Interband and intraband transitions are fundamental concepts in the study of electronic properties of materials, particularly semiconductors and nanomaterials. These transitions involve the movement of electrons between distinct energy states or bands within a material. Besides, charge mobility is also a critical parameter in materials science and electronics. A thorough understanding of these transitions and mobility is critical for the development and optimization of advanced electronic and optoelectronic devices. In this study, we investigate the influence of external periodic drivings on interband and intraband transitions, as well as charge mobility, within a driven two-band model that includes electron-phonon coupling. These external periodic drivings can include a periodic laser field, a time-varying magnetic or electric field, or an alternating current (AC) voltage source. We have developed the Floquet surface hopping (FSH) and Floquet mean field (FMF) methods to simulate electronic dynamics under various drivings in both real and reciprocal spaces. Our findings demonstrate that periodic drivings can enhance interband transitions while suppressing intraband transitions. Additionally, charge mobility is restrained by these external periodic drivings in the driven two-band model.