Floquet engineering spin triplet states in unconventional magnets

TL;DR

This paper explores how high- and low-frequency light drives can induce and control spin triplet states and superconducting correlations in unconventional magnets, revealing new dynamic phases and measurable spin densities.

Contribution

It demonstrates the emergence and control of spin triplet states and superconducting correlations in unconventional magnets through Floquet engineering with light drives.

Findings

High-frequency linearly polarized light induces spin-triplet density in d-wave altermagnets.

Light drives enable formation of odd-frequency spin-triplet superconducting correlations.

Floquet bands broaden superconducting correlations, allowing spin-triplet pairs in various unconventional magnets.

Abstract

We consider unconventional magnets with and without spin-singlet $s$-wave superconductivity and demonstrate the emergence of spin triplet states due to light drives. In particular, we find that a high-frequency linearly polarized light drive induces a spin-triplet density in $d$-wave altermagnets which does not exist in the static regime and can directly reveal the strength of the altermagnetic field. In this high-frequency regime, we also show that linearly polarized light enables the formation of odd-frequency spin-triplet superconducting correlations possessing $d$-wave and $s$-wave parities, which can be controlled by the light drive and accessed by measuring the spin density. Moreover, for low-frequency linearly and circularly polarized light drives, we obtain that the types of superconducting correlations are broadened due to the presence of Floquet bands, enabling spin-triplet pairs in $d$- and $p$-wave unconventional magnets, which are absent in the undriven phase.