Activity in Shirai Labratory



A characteristics of the materials are decided by kinds of atoms and the arrangements of them. In order to make it appear that what kinds of physical mechanisms are cause of the excellent characters, we are researching from the points of microscopic view; atomic and/or electronic level. Then, we educate and investigate in order to plan, develop, and make the materials having more excellent function. Especially, in our research group, the lattice defects in the metall, semiconductors and ceramics are primarily studied by means of positron annihilation methods. Positron is antiparticle to the electron; it has same rest mass as the electron but the opposite charge, therefore, it is very sensitive method to observe the lattice defect such as vacancy, void and dislocation since they are negatively charged and it can also detect unique information about the electronic structure by detecting the g-ray when positron pair-annihilates with the electron. Our technique of positron annihilation method is proud of highest standards in the world, and many new scicntific discoveries have been reported.

Main target
amorphous, semiconductor, ceramic, hydrogenstorage material, heat resisting alloy, superplastic alloy, shape memory alloy, superconductor, thin filmmultilayerdfilm material, nano-crystal
positron annihilation spectroscopy, diffusion and phase transfomation of atoms in solid, theoretical calculation of electronic structure of defect structure

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