Overview of Materials Science Research

Hideaki Takayanagi
Materials Science Laboratory

    The Materials Science Laboratory (MSL) aims at producing new materials by controlling the arrangement and coupling among atoms and molecules. By producing such materials, MSL also aims to discover new quantum phenomena and to create new concepts. Toward these goals, the following four MSL groups investigate a wide variety of materials, from inorganic to organic. The important feature of MSL is the effective sharing of nanofabrication and precise measurement techniques developed originally in each group.

Molecular and Bio-Science Research Group
Creating new organic materials based on the manipulation of single molecules, and researching into information processing devices based on neural functions.

Superconducting Thin Films Research Group
Creating new high-Tc superconductors using the molecular beam epitaxy method.

Superconducting Quantum Physics Research Group
Controlling quantum bits in superconductor as a step towards quantum computing, and creating new magnetic devices using quantum dot arrays.

Nano-Structure Materials Research Group
Developing optical devices for the next generation using photonic crystals.
    The four major results obtained in fiscal year 2000 are as follows.
  1. The real-time monitoring of glutamate (Glu), which are typical neurotransmitters in the cerebral cortex. By fabricating a special electrochemical Glu sensor array, we have succeeded in real-time and multi-site monitoring of this neurotransmitter. This can be regarded as the first step towards understanding the complex neural network in the brain.
  2. High-quality electron-doped cuprate superconducting thin films were prepared by molecular beam epitaxy (MBE) method for the first time. A reduction of the synthesis temperature in MBE makes it possible to synthesize a high-quality thin firm, which cannot be prepared by conventional methods. By investigating the properties of the films, we should find a clear guiding principle for the search for new electron-doped superconductor.
  3. Ferromagnetism in quantum dot superlattices was theoretically predicted. A quantum dot artificial crystal comprising 0.104-μm-wide InAs quantum wires has flat band characteristics. By changing the electron filling of the band, we show that the crystal can be switched from a ferromagnetic to a paramagnetic state and vise versa.
  4. The single-mode, low-loss transmission was achieved in a two dimensional photonic crystals. A photonic crystal, which is an artificial periodical structure consisting of different refractive-index materials, is expected to lead to smaller optical devices and larger scales of integration. We proposed and fabricated line-defect two-dimensional photonic crystals on the SOI (silicon on insulator) structures, and demonstrated the capability of low-loss transmission under the single-mode condition.

    The details of these accomplishments will be described in the following pages.

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