X-ray magnetic circular dichroism originating from the $T_{z}$ term in collinear altermagnets under trigonal crystal field
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arXiv
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| Format: | Preprint |
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2025
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| _version_ | 1866910121553035264 |
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| author | Sasabe, Norimasa Ishii, Yuta Yamasaki, Yuichi |
| author_facet | Sasabe, Norimasa Ishii, Yuta Yamasaki, Yuichi |
| contents | We investigate the microscopic origin and spectral features of X-ray magnetic circular dichroism (XMCD) in collinear antiferromagnets with trigonal crystal fields, using $α$-MnTe as a prototypical example. Although such systems exhibit zero net magnetization, we demonstrate that XMCD can emerge from the anisotropic magnetic dipole operator $T_{z}$, arising from quadrupolar spin distributions. By constructing a complete multipole basis and analyzing the symmetry conditions under trigonal distortion, we identify specific spin and orbital configurations that enable a finite XMCD response. Further, we employ both one-electron and multi-electron models, including spin-orbit coupling and Coulomb interactions, to calculate the XMCD spectra for various $d^n$ configurations. Our findings provide theoretical benchmarks for XMCD in altermagnets and highlight the key role of orbital symmetry and magnetic anisotropy in realizing observable dichroic effects. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2508_17801 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | X-ray magnetic circular dichroism originating from the $T_{z}$ term in collinear altermagnets under trigonal crystal field Sasabe, Norimasa Ishii, Yuta Yamasaki, Yuichi Materials Science We investigate the microscopic origin and spectral features of X-ray magnetic circular dichroism (XMCD) in collinear antiferromagnets with trigonal crystal fields, using $α$-MnTe as a prototypical example. Although such systems exhibit zero net magnetization, we demonstrate that XMCD can emerge from the anisotropic magnetic dipole operator $T_{z}$, arising from quadrupolar spin distributions. By constructing a complete multipole basis and analyzing the symmetry conditions under trigonal distortion, we identify specific spin and orbital configurations that enable a finite XMCD response. Further, we employ both one-electron and multi-electron models, including spin-orbit coupling and Coulomb interactions, to calculate the XMCD spectra for various $d^n$ configurations. Our findings provide theoretical benchmarks for XMCD in altermagnets and highlight the key role of orbital symmetry and magnetic anisotropy in realizing observable dichroic effects. |
| title | X-ray magnetic circular dichroism originating from the $T_{z}$ term in collinear altermagnets under trigonal crystal field |
| topic | Materials Science |
| url | https://arxiv.org/abs/2508.17801 |