Research summary 2004
We study prominent quantum phenomena in condensed matter in a wide temperature range including micro Kelvin region. Development and application of nanostructures to study quantum transport have been carried out. Two-photon photoemission spectroscopy is employed to study electronic properties of adsorbed molecules.
Major achievement and topics are follows: (1) An ultra-low temperature cryostat has been constructed to achieve refrigeration down to 40¦ĚK. The experiment to study the Wigner solid mobility on supeerfluid 3He-A is being planned. (2) A rotation cryostat has been constructed to achieve temperature of 5mK under rotation. Mobility of the Wigner solid on rotating superfluid surface and persistent superfluid current are to be studied. (3) In order to study the mobility of ions trapped under the He surface, an ion emitter based on nanotube is developed (4) To control and detect single electrons on He film and to develop quantum computing, the experimental setup is constructed. (5) Transport of 2D electrons on a thin helium film is observed. Constant decay of electrons from the film surface is a mistery, which we are trying to elucidate. (6) Mesoscopic Hall probe made from GaAs heterostructure is applied for measureing the magnetization process of mesoscopic superconductors. (7) Quantum transport of atomic contact controlled by a mechanical-break-junction technique is to be measured at dilution temperatures. A break junction of organic conductor is made and peculiar non-linear transport is observed. (8) A prominent single electron charging effect of a single gold particle of 10 nanometer in diameter is observed at 4K. (9) A very narrow nano-gap is fabricated, which is characterized by a well-defined tunneling properties.