Ground states of a family of frustrated spin models for quasicrystals and their approximants
Phys. Rev. B 113, 104448 – Published 30 March, 2026
DOI: https://doi.org/10.1103/ht6g-5dwl
Abstract
Many new families of quasicrystal-forming magnetic alloys have been synthesized and studied in recent years. For small changes of composition, the alloys can go from quasiperiodic to periodic (approximant crystals) while conserving most of the local atomic environments. Experiments show that many of the periodic approximants order at low temperatures, with clear signatures of ferromagnetic or antiferromagnetic transitions, and also in some cases undergo nonequilibrium spin glass transitions. In contrast, the quasicrystals are mostly found to be spin glasses. Systematically studying these alloys could help elucidate the role played by quasiperiodicity in (de)stabilizing long-range magnetic order. In this work, we study cluster spin models with the aim of understanding the mechanisms behind various types of long-range magnetic ordering in approximants and quasicrystals. These models embody key features of real systems, and to some extent are analytically tractable, both for periodic and quasiperiodic cases. For the quasicrystal, we describe two possible types of ordered magnetic phases in frustrated regions of the phase diagram. Our results should serve to motivate more detailed numerical explorations of such models so as to gain a better understanding of magnetic phases in quasicrystalline systems.
