Intrinsic nonlinear conductivity induced by quantum geometry in altermagnets and measurement of the in-plane Néel vector
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arXiv
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866913741567688704 |
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| author | Ezawa, Motohiko |
| author_facet | Ezawa, Motohiko |
| contents | The $z$-component of the Néel vector is measurable by the anomalous Hall conductivity in altermagnets because time reversal symmetry is broken. On the other hand, it is a nontrivial problem how to measure the in-plane component of the Néel vector. We study the second-order nonlinear conductivity of a system made of the $d$-wave altermagnet with the Rashba interaction. It is shown that the quantum-metric induced nonlinear conductivity and the nonlinear Drude conductivity are proportional to the in-plane component of the Néel vector, and hence, the in-plane component of the Néel vector is measurable. We obtain analytic formulas of the quantum-metric induced nonlinear conductivity and the nonlinear Drude conductivity both for the longitudinal and transverse conductivities. The quantum-metric induced nonlinear conductivity diverges at the Dirac point, while the nonlinear Drude conductivity is always finite. Hence, the quantum-metric induced nonlinear conductivity is dominant at the Dirac point irrespective of the relaxation time. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2409_09241 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Intrinsic nonlinear conductivity induced by quantum geometry in altermagnets and measurement of the in-plane Néel vector Ezawa, Motohiko Mesoscale and Nanoscale Physics The $z$-component of the Néel vector is measurable by the anomalous Hall conductivity in altermagnets because time reversal symmetry is broken. On the other hand, it is a nontrivial problem how to measure the in-plane component of the Néel vector. We study the second-order nonlinear conductivity of a system made of the $d$-wave altermagnet with the Rashba interaction. It is shown that the quantum-metric induced nonlinear conductivity and the nonlinear Drude conductivity are proportional to the in-plane component of the Néel vector, and hence, the in-plane component of the Néel vector is measurable. We obtain analytic formulas of the quantum-metric induced nonlinear conductivity and the nonlinear Drude conductivity both for the longitudinal and transverse conductivities. The quantum-metric induced nonlinear conductivity diverges at the Dirac point, while the nonlinear Drude conductivity is always finite. Hence, the quantum-metric induced nonlinear conductivity is dominant at the Dirac point irrespective of the relaxation time. |
| title | Intrinsic nonlinear conductivity induced by quantum geometry in altermagnets and measurement of the in-plane Néel vector |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2409.09241 |