Efficient photo-Nernst terahertz emission in single heavy-metal films
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2026
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| author | Wang, Lei Song, Linxuan Chia, Elbert E. M. Sun, Peijie Luo, Jianlin Chen, Rongyan Lau, Yong-Chang Wang, Xinbo |
| author_facet | Wang, Lei Song, Linxuan Chia, Elbert E. M. Sun, Peijie Luo, Jianlin Chen, Rongyan Lau, Yong-Chang Wang, Xinbo |
| contents | State-of-the-art metallic terahertz (THz) emitters rely predominantly on spintronic heterostructures, where heavy metals serve as passive spin-to-charge converters. Here, we demonstrate efficient THz radiation from standalone Pt nanofilms at cryogenic temperatures and under external magnetic fields. The governing mechanism is identified as the ultrafast photo-Nernst effect, wherein a transient thermal gradient drives a transverse charge current. The THz emission polarity is directly dictated by the sign of the Nernst coefficient, as verified by the phase reversal observed between Pt and W or Ta. Remarkably, both thickness scaling and alloying-induced suppression of thermal conductivity independently amplify the single-layer emission to levels comparable with benchmark spintronic bilayers. These findings redefine the established role of heavy metals from passive spin-sinks to active THz emitters, uncovering a universal emission paradigm applicable across diverse spintronic and quantum materials. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_21924 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Efficient photo-Nernst terahertz emission in single heavy-metal films Wang, Lei Song, Linxuan Chia, Elbert E. M. Sun, Peijie Luo, Jianlin Chen, Rongyan Lau, Yong-Chang Wang, Xinbo Mesoscale and Nanoscale Physics Optics State-of-the-art metallic terahertz (THz) emitters rely predominantly on spintronic heterostructures, where heavy metals serve as passive spin-to-charge converters. Here, we demonstrate efficient THz radiation from standalone Pt nanofilms at cryogenic temperatures and under external magnetic fields. The governing mechanism is identified as the ultrafast photo-Nernst effect, wherein a transient thermal gradient drives a transverse charge current. The THz emission polarity is directly dictated by the sign of the Nernst coefficient, as verified by the phase reversal observed between Pt and W or Ta. Remarkably, both thickness scaling and alloying-induced suppression of thermal conductivity independently amplify the single-layer emission to levels comparable with benchmark spintronic bilayers. These findings redefine the established role of heavy metals from passive spin-sinks to active THz emitters, uncovering a universal emission paradigm applicable across diverse spintronic and quantum materials. |
| title | Efficient photo-Nernst terahertz emission in single heavy-metal films |
| topic | Mesoscale and Nanoscale Physics Optics |
| url | https://arxiv.org/abs/2603.21924 |