Ultrafast Spin‐Charge Conversion at SnBi2Te4/Co Topological Insulator Interfaces Probed by Terahertz Emission Spectroscopy

Spin‐to‐charge conversion (SCC) involving topological surface states (TSS) is one of the most promising routes for highly efficient spintronic devices for terahertz (THz) emission. Here, the THz generation generally occurs mainly via SCC consisting in efficient dynamical spin injection into spin‐loc...

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Bibliographic Details
Published in:Advanced optical materials 2022-04, Vol.10 (7), p.n/a
Main Authors: Rongione, E., Fragkos, S., Baringthon, L., Hawecker, J., Xenogiannopoulou, E., Tsipas, P., Song, C., Mičica, M., Mangeney, J., Tignon, J., Boulier, T., Reyren, N., Lebrun, R., George, J.‐M., Le Fèvre, P., Dhillon, S., Dimoulas, A., Jaffrès, H.
Format: Article
Language:English
Subjects:
Bilayers
Conversion
Electrons
Emission analysis
Emission spectroscopy
Ferromagnetism
Materials science
Optics
Photoelectric emission
Spectrum analysis
spin‐charge conversion
terahertz spectroscopy
Topological insulators
topological surface states
ultrafast spintronics
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Summary:Spin‐to‐charge conversion (SCC) involving topological surface states (TSS) is one of the most promising routes for highly efficient spintronic devices for terahertz (THz) emission. Here, the THz generation generally occurs mainly via SCC consisting in efficient dynamical spin injection into spin‐locked TSS. In this work, sizable THz emission from a nanometric thick topological insulator (TI)/ferromagnetic junction—SnBi2Te4/Co—specifically designed to avoid bulk band crossing with the TSS at the Fermi level, unlike its parent material Bi2Te3 is demonstrated. THz emission time domain spectroscopy (TDS) is used to indicate the TSS contribution to the SCC by investigating the TI thickness and angular dependence of the THz emission. This work illustrates THz emission TDS as a powerful tool alongside angular resolved photoemission spectroscopy (ARPES) methods to investigate the interfacial spintronic properties of TI/ferromagnet bilayers. THz emission spectroscopy has an increasingly major role to play in the investigation of the spin‐to‐charge conversion phenomena in the time domain in SnBi2Te4 topological insulator/Co interfaces. Thickness‐independent and crystalline isotropic behavior of the magnetic‐based THz emission are in line with interfacial spin‐charge conversion by inverse Rashba–Edelstein effect like mediated by the topological surface states.
ISSN:2195-1071
2195-1071
DOI:10.1002/adom.202102061