Artificial spin ice on the CaVO lattice: a tricritical bridge from square to kagome
Abstract
Artificial spin ices (ASIs) are arrays of interacting nanomagnets in which phase transitions can be imaged and controlled. Studies of the thermodynamic have focused mainly on the square and kagome lattices, and on their variants. Here we study artificial spin ice on the CaVO lattice, formed of squares and octagons. At fixed lattice constant, the ratio r of the square and octagon link lengths tunes the interactions strongly while changing the geometry only slightly. Magnetic force microscopy and Monte Carlo simulations show a continuous bridge from square-ice-like to kagome-like behavior. At small r the system has a single ordering transition, whereas at large r it passes from a correlated paramagnet to charge order and then long-range order. The two regimes meet in a multicritical region, accurately modeled by a Blume-Capel model of the octagon toroidal moments. From this picture, we design a comparative magnetometry protocol that unambiguously separates interaction effects from single-nanomagnet effects in thermally active samples. Finally, the charge-ordered region maps onto a tunable dimer model, with a Coulomb phase and pinch points along the line between two ordered dimer phases. The CaVO ASI thus provides access to a rich phase diagram only through geometric tuning, without requiring extreme experimental conditions.
Related
- Experimental observation of decoupled spin subsystems in decorated square kagomé lattice magnets of the nabokoite family
- Melting noncoplanar order on the square-kagome lattice: Chiral, flat-band, and staggered spin liquids from projective symmetry
- Collinear and noncollinear antiferromagnetic ordering in a highly frustrated decorated square kagomé lattice antiferromagnets of the nabokoite family
- Collective charge excitations in the kagome lattice driven by Holstein phonons and magnetic fields
- Anisotropic ising model on 2D Kagomé lattice as an inhomogeneous XYZ integrable model
BibTeX
@misc{museur2026artificial,
title = {{Artificial spin ice on the CaVO lattice: a tricritical bridge from square to kagome}},
author = {F. Museur and G. M. Macauley and S. Nilsson and V. Scagnoli and P. M. Derlet and L. J. Heyderman},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.01397},
eprint = {2611.01397},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.01397},
}
RIS
TY - UNPB
TI - Artificial spin ice on the CaVO lattice: a tricritical bridge from square to kagome
AU - F. Museur
AU - G. M. Macauley
AU - S. Nilsson
AU - V. Scagnoli
AU - P. M. Derlet
AU - L. J. Heyderman
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.01397
UR - https://arxiv.org/abs/2611.01397
AB - Artificial spin ices (ASIs) are arrays of interacting nanomagnets in which phase transitions can be imaged and controlled. Studies of the thermodynamic have focused mainly on the square and kagome lattices, and on their variants. Here we study artificial spin ice on the CaVO lattice, formed of squares and octagons. At fixed lattice constant, the ratio r of the square and octagon link lengths tunes the interactions strongly while changing the geometry only slightly. Magnetic force microscopy and Monte Carlo simulations show a continuous bridge from square-ice-like to kagome-like behavior. At small r the system has a single ordering transition, whereas at large r it passes from a correlated paramagnet to charge order and then long-range order. The two regimes meet in a multicritical region, accurately modeled by a Blume-Capel model of the octagon toroidal moments. From this picture, we design a comparative magnetometry protocol that unambiguously separates interaction effects from single-nanomagnet effects in thermally active samples. Finally, the charge-ordered region maps onto a tunable dimer model, with a Coulomb phase and pinch points along the line between two ordered dimer phases. The CaVO ASI thus provides access to a rich phase diagram only through geometric tuning, without requiring extreme experimental conditions.
ER -