Modeling of a twisted-Kagome HoAgGe spin ice using Reduced-Configuration-Space Search and Density Functional Theory

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Autori principali: Schwertfeger, Gunnar F., Chang, Po-Hao, Nikolic, Predrag, Mazin, Igor I.
Natura: Preprint
Pubblicazione: 2025
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author Schwertfeger, Gunnar F.
Chang, Po-Hao
Nikolic, Predrag
Mazin, Igor I.
author_facet Schwertfeger, Gunnar F.
Chang, Po-Hao
Nikolic, Predrag
Mazin, Igor I.
contents The Kagome lattice is a 2D network of corner sharing triangles found in several rare earth materials resulting in a complicated and often frustrated magnetic system. In the last decades, modifications of the motif, such as breathing Kagome, asymmetric Kagome, and twisted Kagome were brought into the limelight. In particular, the latter has lower symmetry than the original Kagome and thus allows implementations of an "Ising-local" Hamiltonian, leading to a 2D spin ice. One such material implementation, HoAgGe, was recently reported to have an exceptionally rich phase diagram and is a strongly frustrated 2D spin-ice material with a twisted-Kagome geometry. In the presence of an external magnetic field the compound exhibits step-like magnetization plateaus at simple fractions of the saturation magnetization. It is believed that this phenomenon results from strong single-site anisotropy, which in HoAgGe was found to be in-plane and along a high-symmetry direction. Previous Monte Carlo simulations with empirical exchange parameters explain some, but not all experimental observations. In this work we present (a) first-principle calculations of the crucial model parameters and (b) direct energy minimization via a Reduced-Configuration-Space search, as well as Monte-Carlo simulations of the field-dependent phase diagram. We find that for HoAgGe the calculated exchange parameters are very different from the earlier suggested empirical ones, and describe the phase diagram much more accurately. This is likely because the first-principles parameters are, in addition to geometrically, also parametrically frustrated.
format Preprint
id arxiv_https___arxiv_org_abs_2507_04146
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Modeling of a twisted-Kagome HoAgGe spin ice using Reduced-Configuration-Space Search and Density Functional Theory
Schwertfeger, Gunnar F.
Chang, Po-Hao
Nikolic, Predrag
Mazin, Igor I.
Strongly Correlated Electrons
Materials Science
The Kagome lattice is a 2D network of corner sharing triangles found in several rare earth materials resulting in a complicated and often frustrated magnetic system. In the last decades, modifications of the motif, such as breathing Kagome, asymmetric Kagome, and twisted Kagome were brought into the limelight. In particular, the latter has lower symmetry than the original Kagome and thus allows implementations of an "Ising-local" Hamiltonian, leading to a 2D spin ice. One such material implementation, HoAgGe, was recently reported to have an exceptionally rich phase diagram and is a strongly frustrated 2D spin-ice material with a twisted-Kagome geometry. In the presence of an external magnetic field the compound exhibits step-like magnetization plateaus at simple fractions of the saturation magnetization. It is believed that this phenomenon results from strong single-site anisotropy, which in HoAgGe was found to be in-plane and along a high-symmetry direction. Previous Monte Carlo simulations with empirical exchange parameters explain some, but not all experimental observations. In this work we present (a) first-principle calculations of the crucial model parameters and (b) direct energy minimization via a Reduced-Configuration-Space search, as well as Monte-Carlo simulations of the field-dependent phase diagram. We find that for HoAgGe the calculated exchange parameters are very different from the earlier suggested empirical ones, and describe the phase diagram much more accurately. This is likely because the first-principles parameters are, in addition to geometrically, also parametrically frustrated.
title Modeling of a twisted-Kagome HoAgGe spin ice using Reduced-Configuration-Space Search and Density Functional Theory
topic Strongly Correlated Electrons
Materials Science
url https://arxiv.org/abs/2507.04146