We study the spatiotemporal dynamics of ultrafast electron spin transport across nanometer-thick copper layers using broadband terahertz spectroscopy. Our analysis of temporal delays, broadening and attenuation of the spin-current pulse revealed ballistic-like propagation of the pulse peak, approaching the Fermi velocity, and diffusive features including a significant velocity dispersion. A comparison to the frequency-dependent Ficks law identified the diffusion-dominated transport regime for distances larger than 2 nm. The findings lie the groundwork for designing future broadband spintronic devices.
@article{arxiv.2310.12082,
title = {Accessing ultrafast spin-transport dynamics in copper using broadband terahertz spectroscopy},
author = {Jiří Jechumtál and Reza Rouzegar and Oliver Gueckstock and Christian Denker and Wolfgang Hoppe and Quentin Remy and Tom S. Seifert and Peter Kubaščík and Georg Woltersdorf and Piet W. Brouwer and Markus Münzenberg and Tobias Kampfrath and Lukáš Nádvorník},
journal= {arXiv preprint arXiv:2310.12082},
year = {2024}
}
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V3: AAM, Licence: CC BY Main text consists of 3 figures and 4 pages of text