Thermal evolution of spin excitations in honeycomb Ising antiferromagnetic FePSe3

Lebing Chen, Xiaokun Teng, Ding Hu, Feng Ye, Garrett E. Granroth, Ming Yi, Jae Ho Chung, Robert J. Birgeneau, Pengcheng Dai

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1 Citation (Scopus)


We use elastic and inelastic neutron scattering (INS) to study the antiferromagnetic (AF) phase transitions and spin excitations in the two-dimensional (2D) zig-zag antiferromagnet FePSe3. By determining the magnetic order parameter across the AF phase transition, we conclude that the AF phase transition in FePSe3 is first-order in nature. In addition, our INS measurements reveal that the spin waves in the AF ordered state have a large easy-axis magnetic anisotropy gap, consistent with an Ising Hamiltonian, and possible biquadratic magnetic exchange interactions. On warming across TN, we find that dispersive spin excitations associated with three-fold rotational symmetric AF fluctuations change into FM spin fluctuations above TN. These results suggest that the first-order AF phase transition in FePSe3 may arise from the competition between C3 symmetric AF and C1 symmetric FM spin fluctuations around TN, in place of a conventional second-order AF phase transition.

Original languageEnglish
Article number40
Journalnpj Quantum Materials
Issue number1
Publication statusPublished - 2024 Dec

Bibliographical note

Publisher Copyright:
© The Author(s) 2024.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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