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arXiv · 2106.09722

Magnetization process and ordering of the $S=1/2$ pyrochlore magnet in a field

Imre Hagymási·Robin Schäfer·Roderich Moessner·David J. Luitz
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Abstract

We study the $S=1/2$ pyrochlore Heisenberg antiferromagnet in a magnetic field. Using large scale density-matrix renormalization group (DMRG) calculations for clusters up to $128$ spins, we find indications for a finite triplet gap, causing a threshold field to nonzero magnetization in the magnetization curve. We obtain a robust saturation field consistent with a magnon crystal, although the corresponding $5/6$ magnetization plateau is very slim and possibly unstable. Most remarkably, there is a pronounced and apparently robust $\frac 1 2$ magnetization plateau where the groundstate breaks (real-space) rotational symmetry, exhibiting oppositely polarised spins on alternating kagome and triangular planes. Reminiscent of the kagome ice plateau of the pyrochlore Ising magnet known as spin ice, it arises via a much more subtle `quantum order by disorder' mechanism.

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Imre Hagymási, Robin Schäfer, Roderich Moessner, David J. Luitz. 2021-06-17. Magnetization process and ordering of the $S=1/2$ pyrochlore magnet in a field. https://doi.org/10.1103/physrevb.106.l060411

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