Volume 3 Issue 12, December 2007

Volume 3 Issue 12

Two-dimensional electron gases provide 'mini laboratories' for fundamental physics as well as the basis for the semiconductor industry. Devices are ultimately limited by the flow of electrons, and a direct visualization of their flow could lead to better designs and applications. To this end, Michael Jura and co-workers use scanning gate microscopy to observe the electrons flowing through samples with different levels of disorder. They find that although the electrons flow along narrow branches, as expected, electrons in the cleanest sample – which still include a few scattering sites – show no hard scattering from impurities and defects. Moreover, the trajectories are stable to changes in the initial injection sites and injection angle. This stability is not expected for classical chaotic motion and quantum mechanical simulations are necessary to explain the results. [Letter p841]


  • Editorial |

    CERN's latest accelerator is taking shape.


  • Commentary |

    Fundamental research can yield unforeseen benefits of great value for society, but often this happens only many years after the initial breakthroughs have been made. Can society find a way to pay back this debt?

    • Leon N Cooper


Books and Arts

Research Highlights

News and Views

  • News & Views |

    The most precise test of time dilation so far assures us that all is well with the special theory of relativity, and sets important benchmarks for practical applications and for emerging theories of quantum gravity.

    • Claus Lämmerzahl
  • News & Views |

    Two papers published in 1957 helped to define the field of nuclear astrophysics. Since then, the field has expanded to include a broad range of phenomena in addition to the origin of the elements.

    • S. E. Woosley
  • News & Views |

    The physics of phase transitions beautifully describes the collective behaviour of many populations of inanimate particles, from water molecules to magnetic spins. But could it also help in understanding ensembles of living neurons?

    • John M. Beggs
  • News & Views |

    The newest form of radioactivity, two-proton decay, has been imaged directly using an optical time-projection chamber. The protons are emitted in a way that reflects the internal dynamics of the parent nucleus.

    • Philip M. Walker
    •  & Ronald C. Johnson
  • News & Views |

    It is fifty years since John Bardeen, Leon Cooper and Bob Schrieffer presented the microscopic theory of superconductivity. At a wonderful conference in Urbana the 'good old days' were remembered, and the challenges ahead surveyed.

    • Michael R. Norman
  • News & Views |

    An antenna for optical frequencies that operates by tuning into the interaction of surface-plasmon polaritons, supported by an array of nanometre-sized holes in a thin metal film, represents another step towards the manipulation of light at the nanoscale.

    • Peter B. Catrysse