Magnon topology driven by altermagnetism
Fuente:
arXiv
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| Autores principales: | , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| Acceso en línea: | |
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| _version_ | 1866915669010808832 |
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| author | Khatua, Subhankar Kravchuk, Volodymyr P. Yershov, Kostiantyn V. Brink, Jeroen van den |
| author_facet | Khatua, Subhankar Kravchuk, Volodymyr P. Yershov, Kostiantyn V. Brink, Jeroen van den |
| contents | Altermagnets present a class of fully compensated collinear magnetic order, where the two sublattices are not related merely by time-reversal combined with lattice translation or inversion, but require an additional lattice rotation. This distinctive symmetry leads to a characteristic splitting of the magnon bands; however the splitting is only partial -- residual degeneracies persist along certain lines in the Brillouin zone as a consequence of the underlying altermagnetic rotation. We consider a two-dimensional $d$-wave altermagnetic spin model on the checkerboard lattice and introduce additional interactions such as an external magnetic field and Dzyaloshinskii-Moriya interactions, that lift these degeneracies. The resulting magnon bands become fully gapped and acquire non-trivial topology, characterized by nonzero Chern numbers. We demonstrate the crucial role of altermagnetism for the generation of the Berry curvature. As a direct consequence of the topological magnons, we find finite thermal Hall conductivity $κ_{xy}$, which exhibits a characteristic low-temperature scaling, $κ_{xy}\propto T^4$. Moreover, $κ_{xy}$ changes sign under reversal of the magnetic field, exhibiting a sharp jump across zero field at low temperatures. We also demonstrate topologically protected chiral edge modes in a finite strip geometry. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_17822 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Magnon topology driven by altermagnetism Khatua, Subhankar Kravchuk, Volodymyr P. Yershov, Kostiantyn V. Brink, Jeroen van den Strongly Correlated Electrons Altermagnets present a class of fully compensated collinear magnetic order, where the two sublattices are not related merely by time-reversal combined with lattice translation or inversion, but require an additional lattice rotation. This distinctive symmetry leads to a characteristic splitting of the magnon bands; however the splitting is only partial -- residual degeneracies persist along certain lines in the Brillouin zone as a consequence of the underlying altermagnetic rotation. We consider a two-dimensional $d$-wave altermagnetic spin model on the checkerboard lattice and introduce additional interactions such as an external magnetic field and Dzyaloshinskii-Moriya interactions, that lift these degeneracies. The resulting magnon bands become fully gapped and acquire non-trivial topology, characterized by nonzero Chern numbers. We demonstrate the crucial role of altermagnetism for the generation of the Berry curvature. As a direct consequence of the topological magnons, we find finite thermal Hall conductivity $κ_{xy}$, which exhibits a characteristic low-temperature scaling, $κ_{xy}\propto T^4$. Moreover, $κ_{xy}$ changes sign under reversal of the magnetic field, exhibiting a sharp jump across zero field at low temperatures. We also demonstrate topologically protected chiral edge modes in a finite strip geometry. |
| title | Magnon topology driven by altermagnetism |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2507.17822 |