Ultrafast controlling net magnetization in g-wave altermagnets via laser fields
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arXiv
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866914332401467392 |
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| author | Zhou, Zhaobo Sharma, Sangeeta He, Junjie |
| author_facet | Zhou, Zhaobo Sharma, Sangeeta He, Junjie |
| contents | The diverse nodal spin structures in d/g/i-wave altermagnets (AM) may cause distinct light-induced spin responses yet remain poorly understood. Using time-dependent density functional theory (TDDFT), we reveal that laser induced ultrafast demagnetization dynamics in the g-wave AM CrSb are strongly governed by the laser incidence direction. Under normal incidence along the [0001] axis, two Cr sublattices exhibit symmetric temporal demagnetization but with different amplitudes, preserving the net-zero magnetization, unlike the behavior in d-wave AM. Off-normal incidence, however, induces pronounced asymmetric demagnetization between sublattices, transiently driving the system into a ferrimagnetic-like state with a sizable net magnetization. This direction-dependent response arises from the characteristic nodal structures in bulk g-wave AM electronic structure, which enable anisotropic optical intersite spin transfer (OISTR). By comparing g-wave and d-wave AMs, we propose that light-induced magnetization arises when laser polarization aligns with spin-uncompensated regions in electronic structures. This can be readily determined from the local spin density of states along specific band paths. Our results provide a fundamental understanding for laser-induced ultrafast dynamics in AM. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2509_14991 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Ultrafast controlling net magnetization in g-wave altermagnets via laser fields Zhou, Zhaobo Sharma, Sangeeta He, Junjie Materials Science Computational Physics The diverse nodal spin structures in d/g/i-wave altermagnets (AM) may cause distinct light-induced spin responses yet remain poorly understood. Using time-dependent density functional theory (TDDFT), we reveal that laser induced ultrafast demagnetization dynamics in the g-wave AM CrSb are strongly governed by the laser incidence direction. Under normal incidence along the [0001] axis, two Cr sublattices exhibit symmetric temporal demagnetization but with different amplitudes, preserving the net-zero magnetization, unlike the behavior in d-wave AM. Off-normal incidence, however, induces pronounced asymmetric demagnetization between sublattices, transiently driving the system into a ferrimagnetic-like state with a sizable net magnetization. This direction-dependent response arises from the characteristic nodal structures in bulk g-wave AM electronic structure, which enable anisotropic optical intersite spin transfer (OISTR). By comparing g-wave and d-wave AMs, we propose that light-induced magnetization arises when laser polarization aligns with spin-uncompensated regions in electronic structures. This can be readily determined from the local spin density of states along specific band paths. Our results provide a fundamental understanding for laser-induced ultrafast dynamics in AM. |
| title | Ultrafast controlling net magnetization in g-wave altermagnets via laser fields |
| topic | Materials Science Computational Physics |
| url | https://arxiv.org/abs/2509.14991 |