[18p-E311-1~18] 6.3 Oxide electronics

[18p-E311-13] Single band two-dimensional hole superconductivity in transparent Li_1−xNbO₂ epitaxial films

〇(D)Takuto Soma¹, Kohei Yoshimatsu¹, Koji Horiba^2,3, Hiroshi Kumigashira^2,3, Akira Ohtomo^1,3 (1.Tokyo Tech., Dept. Chem. Sci. Eng., 2.KEK-PF, 3.MCES)

Keywords:Superconductivity, Layered compound, p-type transparent conductor

Li_1-xNbO₂ is a T_C ~ 5 K superconductor, and it has a stacked structure of Nb triangular lattice planes like transition metal dichalcogenides, which can expect strong two-dimensionality and electron-spin correlation. On the other hand, it is predicted that the O 2p orbital forms a deep energy level and the Nb 4d_z2 band becomes strongly isolated. This suggests that hole superconductivity is realized in a single band, resulting that this material is suitable for investigation of a two-dimensional hole superconductor plane. However, even synthesis of the single crystalline thin film has not ever attained which are necessary for the experiment. Recently, we have developed own three-step synthesis method and succeeded in the synthesis of superconducting epitaxial thin films. In this talk, we would like to report that the evaluation of the two-dimensionality of the superconductivity and electronic structure by the angle-dependent measurement of the superconducting critical magnetic field.