Suppression of ferromagnetism in van der Waals insulator due to pressure-induced layer stacking variation

M. Misek; U. Dutta; P. Kral; D. Hovancik; J. Kastil; K. Pokhrel; S. Ray; J. Valenta; J. Prchal; J. Kamarad; F. Borodavka; V. Eigner; M. Dusek; V. Holy; K. Carva; S. Kamba; V. Sechovsky; J. Pospisil

arXiv · 2501.13446

Suppression of ferromagnetism in van der Waals insulator due to pressure-induced layer stacking variation

M. Misek·U. Dutta·P. Kral·D. Hovancik·J. Kastil·K. Pokhrel·S. Ray·J. Valenta·J. Prchal·J. Kamarad·F. Borodavka·V. Eigner·M. Dusek·V. Holy·K. Carva·S. Kamba·V. Sechovsky·J. Pospisil

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Abstract

Ferromagnetism in van der Waals insulators like CrBr3 is highly sensitive to structural modifications. We explore the pressure-driven structural and magnetic transformations of the van der Waals magnet CrBr3, establishing it as a model platform for phenomena emerging in layered vdW systems. Single-crystal X-ray diffraction revealed intrinsic trimorphism with two known phases (monoclinic and rhombohedral) and a so-far unreported trigonal phase. The paracrystal model well captures the coexistence of the rhombohedral and trigonal phases at ambient conditions. Increasing pressure drives the growth of the AA-stacked trigonal phase at the expense of the rhombohedral phase, which becomes undetectable above 8.4 GPa. Magnetization measurements provided the first direct evidence of a collapse of ferromagnetism above 5.8 GPa. This behavior is attributed to the increasing number of AFM-coupled Cr moments in AA stackings. Ab initio DFT calculations of electronic structure and atomistic simulations of finite-temperature magnetism corroborate the scenario.

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M. Misek, U. Dutta, P. Kral, D. Hovancik, J. Kastil, K. Pokhrel, S. Ray, J. Valenta, J. Prchal, J. Kamarad, F. Borodavka, V. Eigner, M. Dusek, V. Holy, K. Carva, S. Kamba, V. Sechovsky, J. Pospisil. 2025-01-23. Suppression of ferromagnetism in van der Waals insulator due to pressure-induced layer stacking variation. https://arxiv.org/abs/2501.13446

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