简介: |
BaFe2As2-based materials are a prototypical family of iron-based high transition temperature superconductors. Among them, the isovalent pnictogen substituted system BaFe2(As1-xPx)2 appears to be the most suitable system to discuss many physical properties, because it can be grown in a wide substitution range, where very clean and homogeneous single crystals are available. We here discuss three topics related to the unusual electronic properties of this system. First is the superconducting gap structure. In contrast to the electron- and hole-doped systems, BaFe2(As1-xPx)2 has line node. We discuss the detailed nodal structure of this system, which is still controversial. Second is the issue of a quantum critical point (QCP) . An important question is whether high-transition temperature superconductivity is driven by an underlying QCP separating different ground states. We show the presence of the QCP deep inside the superconducting dome by systematic measurements of the superfluid density. Third is unusual electronic state in the normal state. We provide thermodynamic evidence that an electronic nematic phase, a unidirectional self-organized state which breaks rotational symmetry of underlying lattice, develops well above the structural transition and persists to the nonmagnetic superconducting regime. Based on these results, we propose a new phase diagram of iron-pnictide superconductors.
个人简介：
1987 Ph.D Department of Physics, University of Tokyo, Japan
1987-1992 Research Associate at Department of Pure and Applied Science, University of Tokyo,Japan
1992-1994 Postdoctral fellow, Department of Physics, Princeton University, USA
1994-1997 Associate Professor, Department of Physics, Hokkaido University, Japan
1997-2004 Associate Professor, Institute for Solid State Physics, University of Tokyo,Japan
2004-present Professor, Department of Physics, Kyoto university, Japan |
