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Electronic energy scales of CrX3 (X = Cl, Br, and I) using high-resolution x-ray scattering

Chamini S. Pathiraja1, Jayajeewana N. Ranhili1, Deniz Wong2, Christian Schulz2, Yi-De Chuang3, Yu-Cheng Shao4, Di-Jing Huang4, Hsiao-Yu Huang4, Amol Singh4 et al.

Byron Freelon1,*

  • *Contact author: bkfreelo@central.uh.edu
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Phys. Rev. Research 7, 043139 – Published 6 November, 2025

DOI: https://doi.org/10.1103/jdxn-5lw4

Abstract

Chromium trihalides CrX3 (X=Cl, Br, and I) have recently become a focal point of research due to their intriguing low-temperature, layer-dependent magnetic properties that can be manipulated by external stimuli. This makes them essential candidates for spintronic applications. Their magnetic orders are often related to the electronic structure parameters, such as spin-orbit coupling (SOC), Hund’s coupling (JH), p−d covalency, and interorbital Coulomb interactions. Accurately determining such parameters is paramount for understanding CrX3 physics. We have used high-resolution resonant inelastic x-ray scattering spectroscopy to study CrX3 across phase transition temperatures. Ligand field multiplet calculations were used to determine the electronic structure parameters by incorporating the crystal field interactions in a distorted octahedral orientation with C3 symmetry. These methods provide the most detailed description of CrX3 magneto-optical and electronic (energetic) terms to date. The crystal field distortion parameters Dσ and Dτ were experimentally determined, and the energies of d orbitals have been reported. The spectroscopic measurements reveal an energy separation between spin-allowed quartet states and spin-forbidden doublet states, which increases upon going from CrCl3 to CrI3. The role of SOC, for Cr 2p orbitals, in spin-flip excitations has been demonstrated. The determined 10Dq values are in good agreement with the spectrochemical series, and Racah B follows the nephelauxetic effect. Such precise measurements offer insights into the energy design of spintronic devices that utilize quantum state tuning within two-dimensional magnetic materials.

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Phys. Rev. Research 7, 043139– Published 6 November, 2025
  • Received 2 December 2024
  • Accepted 23 September 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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