Orbital-resolved superexchange and topological magnon bands in MXene Fe2C
Abstract
Magnetic MXenes are promising candidates for future spintronics due to their intriguing properties. Nevertheless, the topological properties of magnon bands and superexchange mechanism remain relatively underexplored. In this work, we have calculated the spin wave dispersions for MXene Fe2C using the linear spin wave method, with the exchange coupling parameters obtained from first-principles calculations. Owing to the staggered stacking of two Fe sub-lattices, the interlayer exchange coupling lifts the degeneracy of the ferromagnetic magnon modes. A Dirac point is identified in the magnon bands at the K point. The topological properties of magnon bands, including Berry curvature, valley Chern number and edge states, are further computed by means of a two-band model. We also derive an effective Hamiltonian to explain the magnonic topology, which is protected by the C3v rotational symmetry. To understand the microscopic origin of the exchange couplings that govern the magnon bands, we then construct a refined model integrating perturbation theory and the tight-binding approach. The ferromagnetic superexchange coupling is mediated by the virtual hopping between the d orbitals of two distinct Fe sites via a pair of orthogonal p orbitals at the bridging C site. In detail, the intralayer exchange coupling is governed by the in-plane px and py orbitals, while the out-of-plane pz orbital is responsible for the interlayer exchange coupling. Our results establish a direct link between the orbital-resolved anisotropic superexchange and topological properties of the magnon bands in magnetic MXene Fe2C, providing theoretical guidance for future spintronics applications.
Related
- Intrinsic Orbital Nernst Effect in Real Photonic Bands
- Orbital current rectifier and linear magnon Edelstein effect in p-wave antialtermagnets
- Orbital-selective correlations in kagome flat bands of Co3Sn2S2
- Efficient field-free magnetization switching through orbital-current-enhanced magnon torque.
- Algebraic flat bands and even central-band Chern numbers in a seven-orbital hopping model
BibTeX
@misc{gao2026orbitalresolved,
title = {{Orbital-resolved superexchange and topological magnon bands in MXene Fe$_2$C}},
author = {Qiang Gao and Wei Wang and Shaojin Qi and Guimei Shi and Anbang Guo and Xin Jin and Chen Shen and Xing-Qiu Chen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.16530},
eprint = {2609.16530},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.16530},
}
RIS
TY - UNPB
TI - Orbital-resolved superexchange and topological magnon bands in MXene Fe_2C
AU - Qiang Gao
AU - Wei Wang
AU - Shaojin Qi
AU - Guimei Shi
AU - Anbang Guo
AU - Xin Jin
AU - Chen Shen
AU - Xing-Qiu Chen
PY - 2026
DA - 2026/09/15
PB - arXiv
DO - 10.48550/arxiv.2609.16530
UR - https://arxiv.org/abs/2609.16530
AB - Magnetic MXenes are promising candidates for future spintronics due to their intriguing properties. Nevertheless, the topological properties of magnon bands and superexchange mechanism remain relatively underexplored. In this work, we have calculated the spin wave dispersions for MXene Fe_2C using the linear spin wave method, with the exchange coupling parameters obtained from first-principles calculations. Owing to the staggered stacking of two Fe sub-lattices, the interlayer exchange coupling lifts the degeneracy of the ferromagnetic magnon modes. A Dirac point is identified in the magnon bands at the K point. The topological properties of magnon bands, including Berry curvature, valley Chern number and edge states, are further computed by means of a two-band model. We also derive an effective Hamiltonian to explain the magnonic topology, which is protected by the C_3v rotational symmetry. To understand the microscopic origin of the exchange couplings that govern the magnon bands, we then construct a refined model integrating perturbation theory and the tight-binding approach. The ferromagnetic superexchange coupling is mediated by the virtual hopping between the d orbitals of two distinct Fe sites via a pair of orthogonal p orbitals at the bridging C site. In detail, the intralayer exchange coupling is governed by the in-plane p_x and p_y orbitals, while the out-of-plane p_z orbital is responsible for the interlayer exchange coupling. Our results establish a direct link between the orbital-resolved anisotropic superexchange and topological properties of the magnon bands in magnetic MXene Fe_2C, providing theoretical guidance for future spintronics applications.
ER -