Fractionalized Altermagnets: from neighboring and altermagnetic spin-liquids to spin-symmetric band splitting

TL;DR

This paper explores how quantum fluctuations near altermagnetic order can lead to fractionalized phases with topological order and spin-symmetric band splitting, expanding understanding of complex magnetic states.

Contribution

It introduces a theoretical framework for fractionalized phases near altermagnetism, including the concept of an altermagnetic spin liquid with preserved spin symmetry.

Findings

Identification of long-range altermagnetic orders with non-coplanar orbital altermagnetism

Prediction of fractionalized phases with topological order due to quantum fluctuations

Electronic spectral function shows split Fermi surfaces with spin-rotation symmetry preserved

Abstract

We study quantum-fluctuation-driven fractionalized phases in the vicinity of altermagnetic order. First, the long-range magnetic orders in the vicinity of collinear altermagnetism are identified; these feature a non-coplanar "orbital altermagnet" which has altermagnetic symmetries in spin-rotation invariant observables. We then describe neighboring fractionalized phases with topological order reached when quantum fluctuations destroy long-range spin order, within Schwinger-boson theory and an SU(2) gauge theory of fluctuating magnetism. Discrete symmetries remain broken in some of the fractionalized phases, with the orbital altermagnet becoming an "altermagnetic spin liquid". We compute the electronic spectral function in the doped system, which is characterized by split Fermi surfaces with preserved spin-rotation symmetry.