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arXiv · 2501.13616

Fragile Unconventional Magnetism in RuO$_2$ by Proximity to Landau-Pomeranchuk Instability

Zhuang Qian·Yudi Yang·Shi Liu·Congjun Wu
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Abstract

Altermagnetism has attracted considerable attention for its remarkable combination of spin-polarized band structures and zero net magnetization, making it a promising candidate for spintronics applications. We demonstrate that this magnetic phase represents a case of ``unconventional magnetism," first proposed nearly two decades ago by one of the present authors as part of a broader framework for understanding Landau-Pomeranchuk instabilities in the spin channel, driven by many-body interactions. By systematically analyzing the altermagnetism in RuO$_2$ with first-principles calculations, we reconcile conflicting experimental and theoretical reports by attributing it to RuO$_2$'s proximity to a quantum phase transition. We emphasize the critical role of tuning parameters, such as the Hubbard $U$, hole doping, and epitaxial strain, in modulating quasiparticle interactions near the Fermi surface. This work provides fresh insights into the origin and tunability of altermagnetism in RuO$_2$, highlighting its potential as a platform for investigating quantum phase transitions and the broader realm of unconventional magnetism.

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Zhuang Qian, Yudi Yang, Shi Liu, Congjun Wu. 2025-01-23. Fragile Unconventional Magnetism in RuO$_2$ by Proximity to Landau-Pomeranchuk Instability. https://doi.org/10.1103/physrevb.111.174425

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