Currently, the research themes I am most interested in are related to the "quantum condensed phase" such as spin triplet superconductivity and quantum spin liquid state. The method is to develop new substances and exploit new physical properties that are brought about. As an experimental technique, we are creating a laboratory with a special emphasis on low temperature physics.

These oxide materials have the same crystal structure as the cuprates (i.e. the well-known high-Tc superconductors). In 1994, we discovered superconductivity in the ruthenate Sr₂RuO₄ and since then we have developed a highly collaborative world-wide program of research on these materials.

Ruthenate superconductivity is now believed to result from a revolutionary "spin-triplet" state, in which not only the electronic charges but also the active spins of electrons become superfluid.

All the conventional superconductors and even the high-temperature superconductors of copper oxides are "spin-singlet" superconductors, in which electrons pair up with their spins antiparallel to each other. (Spin is a quantum-mechanical propertiy of an electron, corresponding to the classical concept of rotaion about its own axis, or spinning.)

Sr₂RuO₄ is probably the first example of a spin-triplet superconductor for which details of its pairing state based on its entire electronic structure are nearly understood.

We also actively pursue the novel physics of spin-triplet superconductivity. We grow extremely high quality crystals and investigate their physical properties using various techniques including specific-heat measurements; thereby exploring new superconducting phenomena specific to spin-triplet pairing.