Floquet odd-parity collinear magnets

TL;DR

This paper introduces Floquet odd-parity collinear magnets, a new class of unconventional magnetic states induced in antiferromagnets by circularly polarized light, with potential applications in spintronics.

Contribution

It demonstrates that odd-parity spin splittings can be engineered in collinear antiferromagnets using Floquet theory and symmetry breaking by light irradiation.

Findings

Circularly polarized light induces p- and f-wave magnetic states.

Light irradiation breaks pseudo-time-reversal symmetry in antiferromagnets.

First-principles calculations confirm the emergence of these states in MnPSe3.

Abstract

Altermagnets (AMs), recently discovered unconventional magnets distinct from both ferro- and antiferromagnets, have rapidly emerged as a prominent research topic in condensed matter physics. AMs are characterized by alternating collinear magnetic moments with zero net magnetization in real space, and spin splittings with even-parity symmetry in momentum space. However, their counterparts exhibiting odd-parity spin splittings are generally thought to be absent in collinear magnets. Here, we show that such unconventional odd-parity magnets can be induced from collinear antiferromagnets by symmetry engineering. Remarkably, using effective model analysis within Floquet-theory framework, we demonstrate that circularly polarized light irradiation of conventional antiferromagnetic lattices breaks a spin-preserving pseudo-time-reversal symmetry and induces both $p$- and $f$-wave magnets, realizing novel magnetic states dubbed Floquet odd-parity collinear magnets. Moreover, we also uncover light-induced antiferromagnetic Chern insulating states in the $f$-wave magnets. The proposed Floquet odd-parity magnet is confirmed by first-principles calculations of MnPSe$_{3}$ under circularly polarized light. Our work not only proposes a new class of unconventional magnets, but also opens an avenue for light-induced magnetic phenomena in spintronic applications.