Floquet topological $d+id$ superconductivity induced by chiral many-body interactions

TL;DR

This paper demonstrates that circularly-polarized light can induce a topological $d+id$ superconducting phase in a strongly-coupled Hubbard model, revealing a new dynamical method to realize topological superconductivity.

Contribution

It introduces a Floquet-based approach to show how CPL induces topological $d+id$ superconductivity via chiral spin coupling and three-site terms.

Findings

CPL induces topological $d+id$ pairing in the Hubbard model.

The $d+id$ phase persists at low frequencies and intensities.

Phase diagram shows dependence on laser parameters and temperature.

Abstract

We study how a $d$-wave superconductivity is changed when illuminated by circularly-polarised light (CPL) in the repulsive Hubbard model in the strong-coupling regime. We adopt the Floquet formalism for the Gutzwiller-projected effective Hamiltonian with the time-periodic Schrieffer-Wolff transformation. We find that CPL induces a topological superconductivity with a $d+id$ pairing, which arises from the chiral spin coupling and the three-site term generated by the CPL. The latter term remains significant even for low frequencies and low intensities of the CPL. This is clearly reflected in the obtained phase diagram against the laser intensity and temperature for various frequencies red-detuned from the Hubbard $U$, with the transient dynamics also examined. The phenomenon revealed here can open a novel, dynamical way to induce a topological superconductivity.