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arXiv · 2209.01810

Widely-sweeping magnetic field-temperature phase diagrams for skyrmion-hosting centrosymmetric tetragonal magnets

Satoru Hayami·Yasuyuki Kato
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Abstract

We numerically investigate the stabilization mechanisms of skyrmion crystals under thermal fluctuations and external magnetic field in itinerant centrosymmetric tetragonal magnets. By adopting an efficient steepest descent method with a small computational cost, we systematically construct the magnetic field-temperature phase diagrams of the effective spin model derived from the itinerant electron model on a two-dimensional square lattice. As a result, we find that a square-type skyrmion crystal is stabilized by either or both of the high-harmonic wave-vector interaction and the biquadratic interaction under an external magnetic field. Especially, we discover that the former high-harmonic wave-vector interaction can stabilize the skyrmion crystal only at finite temperatures when its magnitude is small. In addition to the skyrmion crystal, we also find other stable multiple-$Q$ states in the phase diagram. Lastly, we discuss the correspondence of the phase diagrams between the effective spin model and the skyrmion-hosting material GdRu$_2$Si$_2$. The present results suggest a variety of multiple-$Q$ states could be driven by thermal fluctuations and external magnetic fields in centrosymmetric itinerant magnets.

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Satoru Hayami, Yasuyuki Kato. 2022-09-05. Widely-sweeping magnetic field-temperature phase diagrams for skyrmion-hosting centrosymmetric tetragonal magnets. https://doi.org/10.1016/j.jmmm.2023.170547

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