ZPE_Logo
  
Search        
  Create an account Home  ·  Topics  ·  Downloads  ·  Your Account  ·  Submit News  ·  Top 10  
Mission Statement

Modules
· Home
· Forum
· LATEST COMMENTS
· Special Sections
· SUPPORT ZPEnergy
· Advertising
· AvantGo
· Books
· Downloads
· Events
· Feedback
· Link to us
· Private Messages
· Search
· Stories Archive
· Submit News
· Surveys
· Top 10
· Topics
· Web Links
· Your Account

Who's Online
There are currently, 261 guest(s) and 0 member(s) that are online.

You are Anonymous user. You can register for free by clicking here

Events
  • (August 7, 2024 - August 11, 2024) 2024 ExtraOrdinary Technology Conference

  • Hot Links
    Aetherometry

    American Antigravity

    Closeminded Science

    EarthTech

    ECW E-Cat World

    Innoplaza

    Integrity Research Institute

    New Energy Movement

    New Energy Times

    Panacea-BOCAF

    RexResearch

    Science Hobbyist

    T. Bearden Mirror Site

    USPTO

    Want to Know

    Other Info-Sources
    NE News Sites
    AER_Network
    E-Cat World
    NexusNewsfeed ZPE
    NE Discussion Groups
    Energetic Forum
    EMediaPress
    Energy Science Forum
    Free_Energy FB Group
    The KeelyNet Blog
    OverUnity Research
    Sarfatti_Physics
    Tesla Science Foundation (FB)
    Vortex (old Interact)
    Magazine Sites
    Electrifying Times (FB)
    ExtraOrdinary Technology
    IE Magazine
    New Energy Times

    Interesting Links

    Click Here for the DISCLOSURE PROJECT
    SciTech Daily Review
    NEXUS Magazine

    Electron spin and orbits in carbon nanotubes are coupled
    Posted on Saturday, March 29, 2008 @ 23:24:45 GMT by vlad

    Science In a carbon nanotube, electrons can orbit around the tube either clockwise or counterclockwise. Conventional wisdom has been that the spin property of the electron would be the same either way, but Cornell research has shown otherwise. Credit: Cornell University

    Researchers hoping to use carbon nanotubes for quantum computing -- in which the spin of a single electron would represent a bit of data -- may have to change their approaches, according to new Cornell research.


    Cornell physicists have found that the spin of an electron in a carbon nanotube is coupled -- that is, interacts with -- the electron's orbit. The finding means researchers will have to change the way they read out or change spin, but offers a new way to manipulate the spin, by manipulating the orbit.


    At left, the expected result when a magnetic field is applied to a single electron orbiting a carbon nanotube. At right, the result of Cornell experiments shows a difference at zero field, indicating the states are not symmetrical as previously believed. The research is reported in the March 27 issue of the journal Nature by Cornell professors of physics Paul McEuen and Daniel Ralph and former Cornell researchers Shahal Ilani, now at the Weizmann Institute of Science in Israel, and Ferdinand Kuemmeth, now at Harvard University.

    Carbon nanotubes are tiny cylinders whose walls are made of carbon atoms arranged in connected hexagons, sort of like a rolled up tube of chicken wire. Rather than orbiting individual atoms, free electrons in a nanotube orbit around the circumference of the tube. Meanwhile, the electron going around that circle can have its spin oriented in two possible directions. Until now, physicists believed that the four possible states of an electron -- with spin up or down and orbit clockwise or counterclockwise -- must be perfectly equivalent.

    To test this, the researchers used the Cornell NanoScale Science and Technology Facility (CNF) to create a tiny device in which a carbon nanotube about 5 nanometers (nm -- a nanometer is a billionth of a meter, about the length of three atoms in a row) in diameter and 500 nm long was mounted between two electrodes above a silicon structure that allows the application of varying electrical charges to the tube. The design of the device made it possible to create quantum dots containing a small number of electrons, all the way down to a single electron.

    By applying a magnetic field along the axis of the tube and measuring the current flow through the tube, the researchers could determine the energy levels of electrons in the four possible combinations of spin and orbit and found that changing the direction of orbit changes the energy. The orbit of the electron affects its spin and vice versa.

    "This doesn't overrule using nanotubes in quantum computing, but it defines new rules for designing them in nanotubes," Ilani said. "It is also interesting from the fundamental physics point of view, because it is the unique cylindrical topology of nanotubes that allows the electrons to have well-defined orbits and therefore to have this coupling."

    The same experiment was performed with "holes" -- places where an electron is missing, creating the equivalent of a positive charge moving around the tube. Again, it had been believed that the energy of a hole would be the same as that of an electron with the same spin, but the experiment showed otherwise.

    Source: Cornell University
    Via: http://www.physorg.com/news125767527.html

     
    Login
    Nickname

    Password

    Security Code: Security Code
    Type Security Code

    Don't have an account yet? You can create one. As a registered user you have some advantages like theme manager, comments configuration and post comments with your name.

    Related Links
    · More about Science
    · News by vlad


    Most read story about Science:
    100 miles on 4 ounces of water?


    Article Rating
    Average Score: 0
    Votes: 0

    Please take a second and vote for this article:

    Excellent
    Very Good
    Good
    Regular
    Bad


    Options

     Printer Friendly Printer Friendly


    "Electron spin and orbits in carbon nanotubes are coupled" | Login/Create an Account | 1 comment | Search Discussion
    The comments are owned by the poster. We aren't responsible for their content.

    No Comments Allowed for Anonymous, please register

    Researchers discover chromium's hidden magnetic talents (Score: 1)
    by vlad on Wednesday, April 16, 2008 @ 22:37:10 GMT
    (User Info | Send a Message) http://www.zpenergy.com
    Two Dartmouth researchers have determined that the element chromium displays electrical properties of magnets in surprising ways. This finding can be used in the emerging field of “spintronics,” which might someday contribute to new and more energy efficient ways of processing and storing data.

    The study, titled “Electrical effects of spin density wave quantization and magnetic domain walls in chromium,” will be published in the April 17 issue of the journal Nature.

    Electrons have an intrinsic angular momentum, called spin, in addition to their electrical charge. In electronics work, it is the charge of the electron that is used for calculations and transmitting information. In spintronics, it is the electron spin that is exploited.

    “The phenomena that we have discovered are likely to lead to new applications of chromium,” says Yeong-Ah Soh, the lead researcher on the paper and an associate professor of physics and astronomy at Dartmouth. She worked on the study with Ravi Kummamuru, a former post-doctoral research associate at Dartmouth now at the University of Illinois at Urbana-Champagne.

    She goes on to explain that in essence, this indicates that a simple and well-known element, chromium, displays different electrical properties on heating and cooling. These differences reflect subtle internal rearrangements of the electrons and their spins.

    In ferromagnets, the kind of common magnet you might see on a refrigerator, the spins of electrons interact with each other leading to alignment. In antiferromagnets, however, the interactions between neighboring electron spins are such that they are opposed. Researchers have long studied the electrical properties of ferromagnets and the influence of electron spin. Less attention has been paid, according to Soh and Kummamuru, to the influence of spin on the electrical properties in antiferromagnets, where it is more difficult to manipulate, and chromium is special since it is the only simple element that is an antiferromagnet.

    “Antiferromagnets are used in numerous fields: physics, materials science, and chemistry, and they are increasingly used in technology, where they are found in the tiny heads that read the data on computer disc drives,” says Soh. “Our research opens the entire new field of controlled electrical effects at a slightly-larger-than-quantum scale in antiferromagnets. The findings show that not only ferromagnets can be used in spintronics; there is a possibility that antiferromagnets can also be employed to manipulate and store information.”

    Source: Dartmouth College
    Via: http://www.physorg.com/news127581230.html [www.physorg.com]



     

    All logos and trademarks in this site are property of their respective owner. The comments are property of their posters, all the rest © 2002-2016 by ZPEnergy. Disclaimer: No content, on or affiliated with ZPEnergy should be construed as or relied upon as investment advice. While every effort is made to ensure that the information contained on ZPEnergy is correct, the operators of ZPEnergy make no warranties as to its accuracy. In all respects visitors should seek independent verification and investment advice.
    Keywords: ZPE, ZPF, Zero Point Energy, Zero Point Fluctuations, ZPEnergy, New Energy Technology, Small Scale Implementation, Energy Storage Technology, Space-Energy, Space Energy, Natural Potential, Investors, Investing, Vacuum Energy, Electromagnetic, Over Unity, Overunity, Over-Unity, Free Energy, Free-Energy, Ether, Aether, Cold Fusion, Cold-Fusion, Fuel Cell, Quantum Mechanics, Van der Waals, Casimir, Advanced Physics, Vibrations, Advanced Energy Conversion, Rotational Magnetics, Vortex Mechanics, Rotational Electromagnetics, Earth Electromagnetics, Gyroscopes, Gyroscopic Effects

    PHP-Nuke Copyright © 2005 by Francisco Burzi. This is free software, and you may redistribute it under the GPL. PHP-Nuke comes with absolutely no warranty, for details, see the license.