Research areas	Photoemission spectroscopy of high-Tc superconductors and strongly correlated electron systems
Keywords	strongly correlated electron systems, high-Tc superconductivity, angle-resolved photoemission spectroscopy
Themes	We are investigating the mechanism of the high-Tc superconductivity, metal- insulator transition, and orbital ordering in the strongly correlated electron systems by using photoemission spectroscopy. While over thirty years have passed since the discovery of the high-Tc cuprates superconductors, the mechanism of the superconductivity has not been clarified yet. In 2008, a Japanese research group discovered iron-based superconductors, which has given a new impact on the research field of superconductivity. These materials show various complex physical properties originating from strong electron-electron interactions and electron-phonon interactions. In order to approach the origin of the physical properties such as high-Tc superconductivity, photoemission spectroscopy is a powerful tool because one can directly take out electrons from the inside of solids. One can approach the origin of the novel physical properties of the material by analyzing of the electronic structure such as electron energy dispersions, Fermi surfaces, and superconducting gaps.
Major publications	[1]D. Ootsuki, T. Yoshida et al., "Thickness-induced metal to insulator transition in Ru nanosheets probed by photoemission spectroscopy: Effects of disorder and Coulomb interaction", Sci. Rep. 10, 1541 (2020). [2] S. Yamamoto, D. Ootsuki, T. Yoshida et al., "Observation of a Pseudogap in the Vicinity of the Metal-Insulator Transition in the Perovskite-type Vanadium Oxides Nd1-xSrxVO3", J. Phys. Soc. Jpn. 87, 024708 (2018). [3] T. Yoshida et al., “Two-Dimensional and Three-Dimensional Fermi Surfaces of Superconducting BaFe2(As1-xPx)2 and Their Nesting Properties Revealed by Angle-Resolved Photoemission Spectroscopy”, Phys. Rev. Lett. 106, 117001 (2011). [4] T. Yoshida et al., “Universal versus Material-Dependent Two-Gap Behaviors of the High-Tc Cuprate Superconductors: Angle-Resolved Photoemission Study of La2-xSrxCuO4”, Phys. Rev. Lett. 103, 037004 (2009). [5] T. Yoshida et al, “Systematic doping evolution of the underlying Fermi surface of La2-xSrxCuO4”, Phys. Rev. B 74, 224510 (2006). [6] T. Yoshida et al, “Direct Observation of the Mass Renormalization in SrVO3 by Angle Resolved Photoemission Spectroscopy”, Phys. Rev. Lett. 95, 146404 (2005). [7] T. Yoshida et al, “Metallic Behavior of Lightly Doped La2-xSrxCuO4 with a Fermi Surface Forming an Arc”, Phys. Rev. Lett. 91, 027001 (2003).
Professional societies/Research and synergic activities
Teaching Areas	Undergraduate courses Graduate courses (Master's program) Graduate courses (Doctor's program) Undergraduate courses open to all departments
Background

Send message to Professor YOSHIDA, Teppei by mail