Floquet engineering of effective pairing interactions in a doped band insulator

TL;DR

This paper demonstrates how periodic driving fields can be used to enhance and control pairing interactions in doped band insulators, potentially reinforcing superconductivity in correlated electron systems.

Contribution

It introduces a method to tune effective pairing interactions via Floquet engineering in a doped honeycomb lattice model, revealing optimal conditions for enhancing pairing.

Findings

Effective pairing interaction is tunable by driving frequency and amplitude.

Optimal frequency range enhances the two-body bound state.

External light can reinforce superconducting pair states.

Abstract

We investigate the pairing state in a doped band insulator under a periodic driving field. We employ a correlated fermionic model on a honeycomb lattice, in which pairing glue is obtainable via repulsive interactions, and derive an effective model under circularly polarized light. We demonstrate that the effective pairing interaction for doped fermions obtained with the second-order perturbation theory is tunable by the frequency and amplitude of the driving field. We find the optimal frequency range to enhance the pairing interaction and show that the modified effective system can strengthen the two-body bound state. Our study suggests that external driving light can reinforce superconducting pair states in strongly correlated electron systems.