Floquet Engineering Magnetism and Superconductivity in the Square-Lattice Hubbard Model

TL;DR

This paper explores how periodic driving with circularly polarized light influences magnetism and superconductivity in the square-lattice Hubbard model, revealing tunable topological phases and phase transitions.

Contribution

It introduces a diagrammatic Floquet Green's function approach to analyze fluctuation-driven pairing and magnetic phases under periodic driving.

Findings

Discovery of an antiferromagnetic-to-ferromagnetic transition induced by light.

Identification of topological $d+id$-wave superconductivity near magnetic transitions.

Control of superconducting pairing symmetry from $d$-wave to $p$-wave via drive parameters.

Abstract

We study the interplay of magnetic order and superconductivity in the square-lattice Hubbard model under periodic driving with circularly polarized light. Formulating diagrammatic techniques based on the random-phase approximation in terms of Floquet Green's functions, allows us to analyze fluctuation-driven unconventional pairing for weak-to-moderate interactions. The interplay of repulsive interactions and photo-assisted hopping of electrons gives rise to a rich magnetic phase diagram featuring an antiferromagnetic-to-ferromagnetic transition prior to a Floquet Lifshitz transition. Close to the antiferromagnetic transition, topological $d+id$-wave superconductivity prevails in the phase diagram for a wide range of drive parameters. At intermediate-to-high frequency driving near the Floquet Lifshitz transition, superconducting orders are tuned from spin-singlet $d$-wave to spin-triplet $p$-wave character, providing an effective protocol for Floquet engineering topological superconductivity.