• Graphene spintronics: 1D contacts improv

    From ScienceDaily@1:317/3 to All on Fri Feb 11 21:30:36 2022
    Graphene spintronics: 1D contacts improve mobility in nano-scale devices


    Date:
    February 11, 2022
    Source:
    University of Manchester
    Summary:
    Researchers may have cleared a significant hurdle on the path
    to quantum computing, demonstrating step-change improvements in
    the spin transport characteristics of nanoscale graphene-based
    electronic devices.



    FULL STORY ========================================================================== Researchers at The University of Manchester may have cleared a
    significant hurdle on the path to quantum computing, demonstrating
    step-change improvements in the spin transport characteristics of
    nanoscale graphene-based electronic devices.


    ==========================================================================
    The team -- comprising researchers from the National Graphene Institute
    (NGI) led by Dr Ivan Vera Marun, alongside collaborators from Japan
    and including students internationally funded by Ecuador and Mexico --
    used monolayer graphene encapsulated by another 2D material (hexagonal
    boron nitride) in a so- called van der Waals heterostructure with one-dimensional contacts. This architecture was observed to deliver an extremely high-quality graphene channel, reducing the interference or electronic 'doping' by traditional 2D tunnel contacts.

    'Spintronic' devices, as they are known, may offer higher energy
    efficiency and lower dissipation compared to conventional electronics,
    which rely on charge currents. In principle, phones and tablets operating
    with spin-based transistors and memories could be greatly improved in
    speed and storage capacity, exceeding Moore's Law.

    As published in Nano Letters, the Manchester team measured electron
    mobility up to 130,000cm2/Vs at low temperatures (20K or -253oC). For
    purposes of comparison, the only previously published efforts to fabricate
    a device with 1D contacts achieved mobility below 30,000cm2/Vs, and the
    130k figure measured at the NGI is higher than recorded for any other
    previous graphene channel where spin transport was demonstrated.

    The researchers also recorded spin diffusion lengths approaching
    20mm. Where longer is better, most typical conducting materials (metals
    and semiconductors) have spin diffusion lengths <1mm. The value of
    spin diffusion length observed here is comparable to the best graphene spintronic devices demonstrated to date.

    Lead author of the study Victor Guarochico said: "Our work is a
    contribution to the field of graphene spintronics. We have achieved
    the largest carrier mobility yet regarding spintronic devices based
    on graphene. Moreover, the spin information is conserved over distances comparable with the best reported in the literature. These aspects open up
    the possibility to explore logic architectures using lateral spintronic elements where long-distance spin transport is needed." Co-author Chris Anderson added: "This research work has provided exciting evidence for a significant and novel approach to controlling spin transport in graphene channels, thereby paving the way towards devices possessing comparable
    features to advanced contemporary charge-based devices. Building on
    this work, bilayer graphene devices boasting 1D contacts are now being characterised, where the presence of an electrostatically tuneable
    bandgap enables an additional dimension to spin transport control." ========================================================================== Story Source: Materials provided by University_of_Manchester. Note:
    Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Victor H. Guarochico-Moreira, Jose L. Sambricio, Khalid Omari,
    Christopher R. Anderson, Denis A. Bandurin, Jesus
    C. Toscano-Figueroa, Noel Natera-Cordero, Kenji Watanabe, Takashi
    Taniguchi, Irina V.

    Grigorieva, Ivan J. Vera-Marun. Tunable Spin Injection in
    High-Quality Graphene with One-Dimensional Contacts. Nano Letters,
    2022; 22 (3): 935 DOI: 10.1021/acs.nanolett.1c03625 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/02/220211102620.htm

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