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arXiv · 2503.09705

Altermagnets with topological order in Kitaev bilayers

Aayush Vijayvargia·Ezra Day-Roberts·Antia S. Botana·Onur Erten
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Abstract

Building on recent advancements in altermagnetism, we develop a highly-frustrated magnetic model with Kitaev-like interactions that integrates key aspects of both quantum spin liquids and altermagnets. While the ground state is a gapless quantum spin liquid, our analysis indicates that an altermagnetic local order emerges upon the introduction of additional interactions that gap the excitation spectrum and give rise to a $\mathbb{Z}_2 $ topological order. This magnetically-fragmented topological altermagnet has fractionalized fermionic excitations with momentum-dependent splitting, in stark contrast to both standard altermagnets and Kitaev spin liquids. In addition, we discover two more altermagnetic phases, including a pseudo-altermagnet that exhibits splitting in the absence of a local order and a half-altermagnet that possesses only one type of fractionalized excitations, similar to a half-metal. We discuss experimental approaches for detecting these phases, including layer-dependent spin and heat transport. Our results highlight the rich physics that can arise due to the interplay between altermagnetism and fractionalized excitations in quantum magnets.

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Aayush Vijayvargia, Ezra Day-Roberts, Antia S. Botana, Onur Erten. 2025-03-12. Altermagnets with topological order in Kitaev bilayers. https://arxiv.org/abs/2503.09705

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