American Physical Society Acta Medica Okayama 96 9 2017 Pair breaking of multigap superconductivity under parallel magnetic fields in the electric-field-induced surface metallic state 094522 EN Masahiro Nabeta Department of Physics, Okayama University Kenta K. Tanaka Department of Physics, Okayama University Seiichiro Onari Department of Physics, Okayama University Masanori Ichioka Department of Physics, Okayama University The roles of paramagnetic and diamagnetic pair-breaking effects in superconductivity in the electric-field-induced surface metallic state are studied using the Bogoliubov–de Gennes equation when magnetic fields are applied parallel to the surface. The multigap states of the subbands are related to the depth dependence and the magnetic field dependence of the superconductivity. In the Fermi-energy density of states and the spin density, subband contributions successively appear from higher-level subbands with increasing magnetic fields. The characteristic magnetic field dependence may be a key feature to identify the multigap structure of the surface superconductivity. No potential conflict of interest relevant to this article was reported.

American Physical Society Acta Medica Okayama 2469-9950 96 9 2017 In-plane anisotropy of transport coefficients in electronic nematic states: Universal origin of nematicity in Fe-based superconductors 094527 EN Seiichiro Onari Department of Physics, Okayama University Hiroshi Kontani Department of Physics, Nagoya University The origin of the electronic nematicity and its remarkable material dependence are famous longstanding unsolved issues in Fe-based superconductors. To attack these issues, we focus on the in-plane anisotropy of the resistivity: In the nematic state in FeSe, the relationp(x) >p(y) holds, whereP(x)(y) is the resistivity along the longer (shorter) Fe-Fe axis. In contrast, the opposite anisotropy p(x) < p(y) is realized in other undoped Fe-based superconductors. Such nontrivial material dependence is naturally explained in terms of the strongly orbitaldependent inelastic quasiparticle scattering realized in the orbital-ordered state. The opposite anisotropy between FeSe (p(x) >p(y)) and other undoped compounds (P-x < P-y) reflects the difference in the number of hole pockets. We also explain the large in-plane anisotropy of the thermoelectric power in the nematic state. No potential conflict of interest relevant to this article was reported.