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arXiv · 2604.02180

Entropic crystallization of geometrically frustrated magnets on 1/1 approximant Tsai-type quasicrystal

Oscar Novat·Ludovic D. C. Jaubert·Masafumi Udagawa
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Abstract

We have studied the antiferromagnetic Ising model on the icosahedral bcc lattice, as a model system of 1/1 approximant Tsai-type quasicrystals. We addressed thermal equilibrium properties of this system with Markov-chain Monte Carlo simulation supplemented with the parallel tempering technique to accelerate the relaxation dynamics. As a result, we found a second-order phase transition takes place to the magnetic ordered phase with ${\mathbb Z_3}\times {\mathbb Z_2}$ symmetry breaking. Despite the ordering, the low-temperature phase keeps macroscopic degeneracy as identified by finite residual entropy, $\mathcal{S}\sim0.1767/{\rm spin}$. Remarkably, the existence of residual entropy turns out to play a major role in the formation of magnetic order. Generation of domain wall is suppressed, as it reduces the residual entropy locally stored in icosahedra, beyond the gain of configurational entropy due to domain wall patterns. Magnetic order arises out of this competition as entropic crystallization, which manifest universal mechanism of strongly frustrated systems with large geometrical units.

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Oscar Novat, Ludovic D. C. Jaubert, Masafumi Udagawa. 2026-04-02. Entropic crystallization of geometrically frustrated magnets on 1/1 approximant Tsai-type quasicrystal. https://arxiv.org/abs/2604.02180

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