Machine Design
  • Resources
  • Members
  • Directory
  • Webinars
  • WISE
  • CAD Models
  • Advertise
    • Search
  • 3D Printing & CAD
  • AUTOMATION & IIOT
  • Robotics
  • Motion Systems
  • Materials
  • Video
  • Data Sheets
  • Topics
    Industry Markets3D Printing & CADAutomation & IIoTFastening & JoiningMaterialsMechanical & Motion Systems Medical DesignRobotics
    Resources
    Machine Design ResourcesWISE (Workers in Science & Engineering)Company DirectorySearch Data SheetsContributeDigital Edition ArchivesCSIA Exchange
    Members
    ContentBenefitsSubscribe
    Advertise
    https://www.facebook.com/MachineDesignMagazine/
    https://www.linkedin.com/company/10998894
    https://twitter.com/MachineDesign
    https://www.youtube.com/channel/UCXKEiQ9dob20rIqTA7ONfJg
    1. Archive

    Most efficient spin injection ever

    July 11, 2001
    University of Arkansas physicists hit the highest efficiency ever in transferring polarized electrons into a semiconductor surface.

    University of Arkansas physicists hit the highest efficiency ever in transferring polarized electrons into a semiconductor surface. In doing so, they also discovered some of the underlying mechanisms that prevent researchers from successfully injecting spin-polarized electrons into a semiconducting surface.

    The researchers reported their findings in the May 25 issue of Science. Physicists hope to harness the power of electron spin to make multifunctional computational devices, where a single multifunctional device would replace hundreds of conventional devices, leading to faster, smaller electronics that consume less power.

    For about 10 years, researchers have been exploring the idea of exploiting electron spin to enhance the performance of integrated circuits. Spins can rotate in a coherent manner and thus alter the resistance of a device in controlled ways. These properties may lead to greater storage capacity and information processing from spintronic devices.

    Until now, however, injecting spin-polarized electrons into a semiconductor surface has not worked — a high percentage of the electrons change their spin orientation during the injection process. The highest spin efficiency recorded was 40% at 10° Kelvin, a temperature too low for effective use in electronic devices.

    The U of A researchers saw an injection efficiency of 92% into a gallium arsenide (GaAs 110) surface at a temperature of 100°K, the temperature of liquid nitrogen. They used a technique that incorporates a magnetic nickel Scanning Tunneling Microscope (STM) tip to inject electrons that are all oriented in one direction. Measurements of polarization can determine whether or not the electrons retain their spin, a technique called spin-polarized tunneling induced luminescence microscopy (SP-TILM). The STM also lets the researchers correlate surface features in the topography of the semiconductor with the degree of spin disruption.

    Areas with an atomic "step," a spot where the atoms do not form an even surface, cause spin disruption. The particular form of GaAs used in the experiments, GaAs (110), has few steps in it, accounting for the high degree of success in injecting spin-polarized electrons. The places where these steps occurred turned out to be the source of electron disruption, causing the spins to flip.

    U of A researchers explain that it takes a free electron to scatter another electron's spin. Usually within a crystal all electrons are paired up, unless there is a broken bond. In the case of GaAs 110, all the electrons are in filled orbitals, so the spins are stable. There are plenty of surfaces, they say, where the electronic configuration is not as smooth and which would, therefore, be less efficient for use in spintronics.

    The researchers plan to study other semiconductor and ferromagnetic surfaces using the same techniques.

    Sponsored Recommendations

    Smart Factory Solutions that Connect and Protect from Amphenol RF

    Nov. 28, 2023

    Stay Connected and In Control of Your Future Factories with Littelfuse

    Nov. 28, 2023

    Turn to NKK Switches for the Widest Range of Industrial-Savvy Electromechanical Switches

    Nov. 28, 2023

    Unlocking Operational Flexibility in Manufacturing with Industria IoT

    Nov. 28, 2023

    Voice your opinion!

    To join the conversation, and become an exclusive member of Machine Design, create an account today!

    I already have an account

    New

    EXAIR Introduces PEEK ½ NPT Super Air Nozzle

    Using Natural Language Understanding to Power Productivity

    Intelligent Assistant Platforms Improve Conversations with Industrial Robots

    Most Read

    Universal Robots Unveils UR30: Relief for Heavy Lifting

    AI: Unleashing the Power in Manufacturing

    How Much Should a Bolted Joint be Tightened?

    Machine Design
    https://www.facebook.com/MachineDesignMagazine/
    https://www.linkedin.com/company/10998894
    https://twitter.com/MachineDesign
    https://www.youtube.com/channel/UCXKEiQ9dob20rIqTA7ONfJg
    • About Us
    • Contact Us
    • Advertise
    • Do Not Sell or Share
    • Privacy & Cookie Policy
    • Terms of Service
    © 2023 Endeavor Business Media, LLC. All rights reserved.
    Endeavor Business Media Logo