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  • Letter
  • Open Access

Terahertz generation via the inverse orbital Rashba-Edelstein effect at the Ni/CuOx interface

Renyou Xu1,*, Xiaobai Ning1,*, Houyi Cheng1,2,3,*, Yuxuan Yao1, Zejun Ren4, Shaojie Liu5, Mingcong Dai4, Yong Xu1, Sai Li1 et al.

Ao Du1, Xiaojun Wu4, Fengxia Hu6, Baogen Shen6, Jirong Sun6, Hui Zhang1,†, and Weisheng Zhao1,2,‡

  • 1Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing 100191, China
  • 2National Key Laboratory of Spintronics, Hangzhou International Innovation Institute, Beihang University, Hangzhou 311115, China
  • 3Truth Equipment Corporation, TREC, Hefei 230013, China
  • 4School of Electronic and Information Engineering, Beihang University, Beijing 100191, China
  • 5Department of Physics, Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
  • 6Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China

  • *These authors contributed equally to this work.
  • †Contact author: huizh@buaa.edu.cn
  • ‡Contact author: weisheng.zhao@buaa.edu.cn
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Phys. Rev. Research 7, L012042 – Published 25 February, 2025

DOI: https://doi.org/10.1103/PhysRevResearch.7.L012042

Abstract

Orbitronics provides novel mechanisms to generate terahertz (THz) emission using the orbital angular momentum of electrons. Here, we report a systematic investigation of the THz emission from Ni/CuOx heterostructures pumped by a femtosecond laser pulse. Despite the very weak spin-orbit coupling of CuOx, considerable THz radiation from Ni/CuOx has been observed, with a polarity state that is magnetically controllable and the intensity as much as about 20% of that found in Ni/Pt spintronic THz emitter. We find conclusive evidence that THz radiation stems from the inverse orbital Rashba-Edelstein effect at the Ni/CuOx interface, which can be manipulated by tuning oxygen-induced orbital hybridization. Our experimental results of Ni thickness-dependent THz emission, combined with theoretical modeling, reveal long-range diffusion-length characteristics of orbital current within the Ni layer. This work enhances the understanding of the THz emission mechanism based on orbital-to-charge conversion, providing guidance for the development of orbitronic THz emitters.

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Phys. Rev. Research 7, L012042– Published 25 February, 2025
  • Received 5 June 2024
  • Accepted 1 November 2024
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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