Condensed Spin Excitation of Quantized Dirac Fermions in the Quasi-Two-Dimensional semimetal BaMnBi$_2$
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arXiv
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| Auteurs principaux: | , , , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866910034476138496 |
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| author | Kumazaki, Masashi Temurjonov, Azimjon Watanabe, Yukihiro Matsuhita, Taku Kobayashi, Yoshiaki Shimizu, Yasuhiro |
| author_facet | Kumazaki, Masashi Temurjonov, Azimjon Watanabe, Yukihiro Matsuhita, Taku Kobayashi, Yoshiaki Shimizu, Yasuhiro |
| contents | Dirac semimetals provide a new platform for the quantum Hall effect at low magnetic fields. In the presence of strong spin-orbit coupling, a spin-split Landau level is expected to enhance the bulk quasiparticle excitation. Here we report NMR spectroscopy that site-selectively probes dynamic spin susceptibility on the magnetic semimetal BaMnBi$_2$. We find that spontaneous staggered fields from antiferromagnetic Mn moments are completely canceled at the Bi layer hosting Dirac fermions. The nuclear spin-lattice relaxation rate $1/T_1$ follows the cubic temperature dependence down to low temperatures under the in-plane field, manifesting the chemical potential close to the Dirac point. $1/T_1$ becomes constant below 20 K under the out-of-plane field, where the well-separated Laudau level appears. The strong anisotropy of $1/T_1$ exceeding 100 suggests spin-split Landau levels in the quantum Hall regime. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2508_07820 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Condensed Spin Excitation of Quantized Dirac Fermions in the Quasi-Two-Dimensional semimetal BaMnBi$_2$ Kumazaki, Masashi Temurjonov, Azimjon Watanabe, Yukihiro Matsuhita, Taku Kobayashi, Yoshiaki Shimizu, Yasuhiro Strongly Correlated Electrons Dirac semimetals provide a new platform for the quantum Hall effect at low magnetic fields. In the presence of strong spin-orbit coupling, a spin-split Landau level is expected to enhance the bulk quasiparticle excitation. Here we report NMR spectroscopy that site-selectively probes dynamic spin susceptibility on the magnetic semimetal BaMnBi$_2$. We find that spontaneous staggered fields from antiferromagnetic Mn moments are completely canceled at the Bi layer hosting Dirac fermions. The nuclear spin-lattice relaxation rate $1/T_1$ follows the cubic temperature dependence down to low temperatures under the in-plane field, manifesting the chemical potential close to the Dirac point. $1/T_1$ becomes constant below 20 K under the out-of-plane field, where the well-separated Laudau level appears. The strong anisotropy of $1/T_1$ exceeding 100 suggests spin-split Landau levels in the quantum Hall regime. |
| title | Condensed Spin Excitation of Quantized Dirac Fermions in the Quasi-Two-Dimensional semimetal BaMnBi$_2$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2508.07820 |