Field-induced Multi-$\boldsymbol{\vec{Q}}$ States in a Pyrochlore Heisenberg Magnet

Fuente: arXiv
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Main Authors: Glittum, Cecilie, Syljuåsen, Olav F.
Format: Preprint
Published: 2025
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author Glittum, Cecilie
Syljuåsen, Olav F.
author_facet Glittum, Cecilie
Syljuåsen, Olav F.
contents We construct exact ground states of the $J_1$-$J_{3b}$ classical Heisenberg model on the pyrochlore lattice in the presence of a magnetic field. They are non-coplanar multi-$\vec{Q}$ spin configurations with a large magnetic unit cell that generalize the previously found coplanar sublattice pairing states. Using linear spin wave theory, we show that entropy favors these multi-$\vec{Q}$ states at low temperatures in high magnetic fields. This is confirmed by Monte Carlo simulations, and a phase diagram is constructed. We also calculate the zero-temperature dynamical structure factor. Besides the usual Goldstone modes associated with the ordering $\vec{Q}$s, we find high intensity gapless modes at momenta where there are no Bragg peaks.
format Preprint
id arxiv_https___arxiv_org_abs_2503_05353
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Field-induced Multi-$\boldsymbol{\vec{Q}}$ States in a Pyrochlore Heisenberg Magnet
Glittum, Cecilie
Syljuåsen, Olav F.
Strongly Correlated Electrons
We construct exact ground states of the $J_1$-$J_{3b}$ classical Heisenberg model on the pyrochlore lattice in the presence of a magnetic field. They are non-coplanar multi-$\vec{Q}$ spin configurations with a large magnetic unit cell that generalize the previously found coplanar sublattice pairing states. Using linear spin wave theory, we show that entropy favors these multi-$\vec{Q}$ states at low temperatures in high magnetic fields. This is confirmed by Monte Carlo simulations, and a phase diagram is constructed. We also calculate the zero-temperature dynamical structure factor. Besides the usual Goldstone modes associated with the ordering $\vec{Q}$s, we find high intensity gapless modes at momenta where there are no Bragg peaks.
title Field-induced Multi-$\boldsymbol{\vec{Q}}$ States in a Pyrochlore Heisenberg Magnet
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2503.05353