An anomalous softening of a special phonon mode in high-Tc superconductors is discovered by using both neutron and X-ray scattering techniques. Particularly, the recent neutron scattering experiment clearly observed a giant phonon softening. This discovery will clarify the role of electron-phonon coupling for the mechanism of high-Tc superconductivity. The result is published in Nature April 27 in 2006. (The results of X-ray scattering was already published in Physical Review B in 2005).
Prof. Yamada group （Neutron and gamma-Ray Spectroscopy on Condensed Matters）