The discovery of high temperature superconducting cuprates in 1986 has brought the physics of superconductivity to a new world of one-order higher temperature. Although a tremendous amount of research has been carried out there remain many mysteries. The problem is not only to elucidate the mechanism of superconductivity but also to understand many anomalous phenomena such as charge segregation. Study of these new phenomena is of great importance, leading to the development of a new field of physics.
We are also investigating the anomalous properties of systems with strong electron-electron or electron-phonon interaction. Transition-metal oxides have a variety of intriguing physical properties other than high-Tc superconductivity such as colossal magnetoresistance. In particular, colossal magnetoresistive manganites have aroused great interest in the interplay among spin, charge, orbital, and lattice degrees of freedom. We investigate critical behaviors near the metal-insulator transition and the orbital order-disorder transition, controlling the orbital order and related electronic state.
In order to research these subjects, we use various measurement techniques such as optical spectroscopy, Raman scattering spectroscopy, THz time-domain spectroscopy as well as transport and magnetic measurements on crystals that we grow ourselves.
Raman scattering spectrometer
(Ar-Kr laser and Jobin Yvon triple monochromator with cryostat and microscope system)
Femtosecond Ti-Sapphire laser and time-domain spectroscopy system in THz region.