Our goal is to discover new materials and novel physical phenomena in the f -electron systems including actinide and rare-earth elements. These systems are known as heavy fermion systems with strong electronic correlations. The f -electrons exhibit a dual nature of both localization and itinerancy, resulting in effective mass of conduction electrons reaching values 100-1000 times larger than the rest mass of an electron. Notably, actinide compounds show a variety of interesting physical phenomena due to this dual nature. For example, some of neptunium and plutonium compounds show “high Tc” superconductivity and complex magnetism based on the multipole interactions. NpPd5Al2 is the first neptunium-based heavy fermion superconductor discovered in our group. Our main focus is also to study the coexistence of ferromagnetism and superconductivity, multiple superconductivity in uranium-based compounds. Unconventional superconductivity is realized in these systems with the spin-triplet state, which attracts much attention because of topological superconductivity and emergence of Majorana particles.
To explore this physics, it is crucial to develop new materials and to grow high quality single crystals. Our laboratory is one of the few facilities in the world capable of handling actinide materials for solid state physics. We investigate not only the basic properties such as structural analysis, specific heat, magnetization, resistivity measurements, but also de Haas-van Alphen experiments and transport measurements under extreme conditions (low temperature, high field, high pressure). Our research is also based on the domestic and international collaborations with other groups.
