Efficient Terahertz Generation from CoPt-based Terahertz Emitters via Orbital-to-Charge Conversion

Fuente: arXiv
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Main Authors: Liu, Yongshan, Xu, Yong, Fert, Albert, Jaffres, Henri-Yves, Eimer, Sylvain, Nie, Tianxiao, Zhang, Xiaoqiang, Zhao, Weisheng
Format: Preprint
Published: 2024
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author Liu, Yongshan
Xu, Yong
Fert, Albert
Jaffres, Henri-Yves
Eimer, Sylvain
Nie, Tianxiao
Zhang, Xiaoqiang
Zhao, Weisheng
author_facet Liu, Yongshan
Xu, Yong
Fert, Albert
Jaffres, Henri-Yves
Eimer, Sylvain
Nie, Tianxiao
Zhang, Xiaoqiang
Zhao, Weisheng
contents Orbitronics devices operate by manipulating orbitally-polarized currents. Recent studies have shown that these orbital currents can be excited by femtosecond laser pulses in ferromagnet as Ni and converted into ultrafast charge current via orbital-to-charge conversion. However, the terahertz emission from orbitronic terahertz emitter based on Ni is still much weaker than the typical spintronic terahertz emitter. Here, we report more efficient light-induced generation of orbital current from CoPt alloy and the orbitronic terahertz emission by CoPt/Cu/MgO shows terahertz radiation comparable to that of efficient spintronic terahertz emitters. By varying the concentration of CoPt alloy, the thickness of Cu, and the capping layer, we confirm that THz emission primarily originates from the orbital accumulation generated within CoPt, propagating through Cu and followed by the subsequent orbital-to-charge conversion from the inverse orbital Rashba-Edelstein effect at the Cu/MgO interface. This study provides strong evidence for the very efficient orbital current generation in CoPt alloy, paving the way to efficient orbital terahertz emitters.
format Preprint
id arxiv_https___arxiv_org_abs_2402_09228
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Efficient Terahertz Generation from CoPt-based Terahertz Emitters via Orbital-to-Charge Conversion
Liu, Yongshan
Xu, Yong
Fert, Albert
Jaffres, Henri-Yves
Eimer, Sylvain
Nie, Tianxiao
Zhang, Xiaoqiang
Zhao, Weisheng
Mesoscale and Nanoscale Physics
Orbitronics devices operate by manipulating orbitally-polarized currents. Recent studies have shown that these orbital currents can be excited by femtosecond laser pulses in ferromagnet as Ni and converted into ultrafast charge current via orbital-to-charge conversion. However, the terahertz emission from orbitronic terahertz emitter based on Ni is still much weaker than the typical spintronic terahertz emitter. Here, we report more efficient light-induced generation of orbital current from CoPt alloy and the orbitronic terahertz emission by CoPt/Cu/MgO shows terahertz radiation comparable to that of efficient spintronic terahertz emitters. By varying the concentration of CoPt alloy, the thickness of Cu, and the capping layer, we confirm that THz emission primarily originates from the orbital accumulation generated within CoPt, propagating through Cu and followed by the subsequent orbital-to-charge conversion from the inverse orbital Rashba-Edelstein effect at the Cu/MgO interface. This study provides strong evidence for the very efficient orbital current generation in CoPt alloy, paving the way to efficient orbital terahertz emitters.
title Efficient Terahertz Generation from CoPt-based Terahertz Emitters via Orbital-to-Charge Conversion
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2402.09228