Optically induced topological superconductivity via Floquet interaction engineering

TL;DR

This paper proposes a method to induce topological superconductivity in a two-valley semiconductor using Floquet engineering with circularly polarized light, leading to chiral pairing states with potential topological properties.

Contribution

It introduces a novel mechanism for light-induced unconventional superconductivity through Floquet interaction engineering in a massive Dirac band structure.

Findings

Control of pump detuning induces different chiral superconducting states.

Floquet engineering modifies Coulomb interactions to favor unconventional pairing.

The system can host topologically protected chiral bound states.

Abstract

We propose a mechanism for light-induced unconventional superconductivity in a two-valley semiconductor with a massive Dirac type band structure. The superconducting phase results from the out-of-equilibrium excitation of carriers in the presence of Coulomb repulsion and is stabilized by coupling the driven semiconductor to a bosonic or fermionic thermal bath. We consider a circularly-polarized light pump and show that by controlling the detuning of the pump frequency relative to the band gap, different types of chiral superconductivity would be induced. The emergence of novel superconducting states, such as the chiral $p$-wave pairing, results from the Floquet engineering of the interaction. This is realized by modifying the form of the Coulomb interaction by projecting it into the states that are resonant with the pump frequency. We show that the resulting unconventional pairing in our system can host topologically protected chiral bound states. We discuss a promising experimental platform to realize our proposal and detect the signatures of the emergent superconducting state.