Marginal Metals and Kosterlitz-Thouless Type Phase Transition in Disordered Altermagnets

Fuente: arXiv
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Main Authors: Li, Chang-An, Fu, Bo, Guo, Huaiming, Trauzettel, Björn, Zhang, Song-Bo
Format: Preprint
Published: 2025
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_version_ 1866911547580743680
author Li, Chang-An
Fu, Bo
Guo, Huaiming
Trauzettel, Björn
Zhang, Song-Bo
author_facet Li, Chang-An
Fu, Bo
Guo, Huaiming
Trauzettel, Björn
Zhang, Song-Bo
contents Altermagnetism, a recently discovered magnetic phase characterized by spin-split bands without net magnetization, has emerged as promising platform for novel physics and potential applications. However, its stability against disorder-ubiquitous in real materials-remains poorly understood. Here, we study the electron localization properties of two-dimensional $d$-wave altermagnets subject to disorder. Remarkably, we discover a disorder-driven phase transition from a marginal metallic phase to an insulator, which falls into the Kosterlitz-Thouless class. We demonstrate this by strong numerical evidence and propose an interpretation in terms of vortex-antivortex pairs in the disorder-induced local in-plane spin magnetization. Moreover, we show that the characteristic spin anisotropy of altermagnets persists but gradually fades away across the transition. These changes directly affect the spin splitting features that are detectable in angle-resolved photoemission spectroscopy and tunneling magnetoconductance. Our findings provide a new perspective on recent experimental observations of altermagnetism in candidate materials.
format Preprint
id arxiv_https___arxiv_org_abs_2507_10762
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Marginal Metals and Kosterlitz-Thouless Type Phase Transition in Disordered Altermagnets
Li, Chang-An
Fu, Bo
Guo, Huaiming
Trauzettel, Björn
Zhang, Song-Bo
Mesoscale and Nanoscale Physics
Altermagnetism, a recently discovered magnetic phase characterized by spin-split bands without net magnetization, has emerged as promising platform for novel physics and potential applications. However, its stability against disorder-ubiquitous in real materials-remains poorly understood. Here, we study the electron localization properties of two-dimensional $d$-wave altermagnets subject to disorder. Remarkably, we discover a disorder-driven phase transition from a marginal metallic phase to an insulator, which falls into the Kosterlitz-Thouless class. We demonstrate this by strong numerical evidence and propose an interpretation in terms of vortex-antivortex pairs in the disorder-induced local in-plane spin magnetization. Moreover, we show that the characteristic spin anisotropy of altermagnets persists but gradually fades away across the transition. These changes directly affect the spin splitting features that are detectable in angle-resolved photoemission spectroscopy and tunneling magnetoconductance. Our findings provide a new perspective on recent experimental observations of altermagnetism in candidate materials.
title Marginal Metals and Kosterlitz-Thouless Type Phase Transition in Disordered Altermagnets
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2507.10762