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Tokiwa, Yoshifumi; Sakai, Hironori; Kambe, Shinsaku; Opletal, P.; Yamamoto, Etsuji; Kimata, Motoi*; Awaji, Satoshi*; Sasaki, Takahiko*; Yanase, Yoichi*; Haga, Yoshinori; et al.
Physical Review B, 108(14), p.144502_1 - 144502_5, 2023/10
Times Cited Count：4 Percentile：52.62(Materials Science, Multidisciplinary)The vortex dynamics in the spin-triplet superconductor, UTe, are studied by measuring the DC electrical resistivity with currents along the 
-axis under magnetic fields along the 
-axis. Surprisingly, we have discovered an island region of low critical current deep inside the superconducting (SC) state, well below the SC upper critical field, attributed to a weakening of vortex pinning. Notably, this region coincides with the recently proposed intermediate-field SC state. We discuss the possibility of nonsingular vortices in the intermediate state, where SC order parameter does not vanish entirely in the vortex cores due to the mixing of multiple SC components.
Higemoto, Wataru; Yokoyama, Makoto*; Ito, Takashi; Suzuki, Taiga*; Raymond, S.*; Yanase, Yoichi*
Proceedings of the National Academy of Sciences of the United States of America, 119(49), p.e2209549119_1 - e2209549119_6, 2022/11
Times Cited Count：2 Percentile：32.89(Multidisciplinary Sciences)no abstracts in English
Aoki, Dai*; Sakai, Hironori; Opletal, P.; Tokiwa, Yoshifumi; Ishizuka, Jun*; Yanase, Yoichi*; Harima, Hisatomo*; Nakamura, Ai*; Li, D.*; Homma, Yoshiya*; et al.
Journal of the Physical Society of Japan, 91(8), p.083704_1 - 083704_5, 2022/08
Times Cited Count：47 Percentile：98.21(Physics, Multidisciplinary)Aoki, Dai*; Brison, J.-P.*; Flouquet, J.*; Ishida, Kenji*; Knebel, G.*; Tokunaga, Yo; Yanase, Yoichi*
Journal of Physics; Condensed Matter, 34(24), p.243002_1 - 243002_41, 2022/06
Times Cited Count：103 Percentile：91.30(Physics, Condensed Matter)Higashi, Yoichi*; Nagai, Yuki; Yoshida, Tomohiro*; Masaki, Yusuke*; Yanase, Yoichi*
Physical Review B, 93(10), p.104529_1 - 104529_10, 2016/03
Times Cited Count：11 Percentile：45.04(Materials Science, Multidisciplinary)no abstracts in English
Higashi, Yoichi*; Nagai, Yuki; Yoshida, Tomohiro*; Kato, Masaru*; Yanase, Yoichi*
Physica C, 518, p.1 - 4, 2015/11
Times Cited Count：0 Percentile：0.00(Physics, Applied)We study the excitation spectra and the wave functions of quasiparticle bound states at a vortex and an edge in bilayer Rashba superconductors under a magnetic field. In particular, we focus on the quasiparticle states at the zero energy in the pair- density wave state in a topologically non-trivial phase. We numerically demonstrate that the quasiparticle wave functions with zero energy are localized at both the edge and the vortex core if the magnetic field exceed the critical value.
Higashi, Yoichi*; Nagai, Yuki; Yoshida, Tomohiro*; Yanase, Yoichi*
Journal of Physics; Conference Series, 568(2), p.022018_1 - 022018_5, 2014/12
Times Cited Count：4 Percentile：81.53(Physics, Applied)We numerically study the electronic structure of a single vortex in two dimensional superconducting bilayer systems within the range of the mean-field theory. The lack of local inversion symmetry in the system is taken into account through the layer dependent Rashba spin-orbit coupling. The spatial profiles of the pair potential and the local quasiparticle density of states are calculated in the clean spin-singlet superconductor on the basis of the quasiclassical theory. In particular, we discuss the characteristic core structure in the pair-density wave state, which is spatially modulated exotic superconducting phase in a high magnetic field.
Si superconductorOkazaki, Ryuji*; Shimozawa, Masaaki*; Shishido, Hiroaki*; Konczykowski, M.*; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Onuki, Yoshichika; Yanase, Yoichi*; Shibauchi, Takasada*; et al.
Journal of Physics; Conference Series, 273, p.012081_1 - 012081_4, 2011/02
Times Cited Count：3 Percentile：62.06(Physics, Condensed Matter)SiOkazaki, Ryuji*; Shimozawa, Masaaki*; Shishido, Hiroaki*; Konczykowski, M.*; Haga, Yoshinori; Matsuda, Tatsuma; Yamamoto, Etsuji; Onuki, Yoshichika; Yanase, Yoichi*; Shibauchi, Takasada*; et al.
Journal of the Physical Society of Japan, 79(8), p.084705_1 - 084705_7, 2010/08
Times Cited Count：16 Percentile：65.62(Physics, Multidisciplinary)Yanase, Yoichi*; Jujo, Takanobu*; Nomura, Takuji; Ikeda, Hiroaki*; Hotta, Takashi; Yamada, Kosaku*
Physics Reports; A Review Section of Physics Letters, 387(1-4), p.1 - 149, 2003/11
Times Cited Count：217 Percentile：83.45(Physics, Multidisciplinary)In this article we review essential natures of superconductivity in strongly correlated electron systems from a universal point of view. Here we consider materials such as high-
cuprates, BEDT-TTF organic superconductors, ruthenate SrRuO
, and heavy fermion superconductors. After the review of experimental results, we explain the formalism to discuss superconducting properties of strongly correlated electron systems based on the Dyson-Gor'kov equations. Then, we introduce theoretical retults on cuprates, organics, ruthenate, and heavy fermion superconductors in this order.
Tokiwa, Yoshifumi; Opletal, P.; Sakai, Hironori; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo; Haga, Yoshinori; Kimata, Motoi*; Awaji, Satoshi*; Sasaki, Takahiko*; et al.
no journal, ,
In unconventional superconductors, there are cases of vortex liquid-like state. When the pinning is strong, vortices do not move, and thus, the formation of such abnormal states requires pure and pristine crystals. Recently, the growth of pure single crystals of the spin-triplet superconductor UTe using a molten salt flux has been reported. In this study, we report research on vortices in UTe using such pure single crystals. As a result, in the magnetic field range of 15 T to 22 T, the critical current showed a maximum in temperature dependence, and a low-temperature region with a low critical current was observed deep in the superconducting state. This low critical current region matches the recently reported intermediate field superconducting phase. This suggests a weakening of the pinning force and a decrease in the critical current in the intermediate field superconducting phase.
Tokiwa, Yoshifumi; Opletal, P.; Sakai, Hironori; Yamamoto, Etsuji; Kambe, Shinsaku; Tokunaga, Yo; Haga, Yoshinori; Kimata, Motoi*; Awaji, Satoshi*; Sasaki, Takahiko*; et al.
no journal, ,
In unconventional superconductors, there are cases of vortex liquid-like state. When the pinning is strong, vortices do not move, and thus, the formation of such abnormal states requires pure and pristine crystals. Recently, the growth of pure single crystals of the spin-triplet superconductor UTe using a molten salt flux has been reported. In this study, we report research on vortices in UTe using such pure single crystals. As a result, in the magnetic field range of 15 T to 22 T, the critical current showed a maximum in temperature dependence, and a low-temperature region with a low critical current was observed deep in the superconducting state. This low critical current region matches the recently reported intermediate field superconducting phase. This suggests a weakening of the pinning force and a decrease in the critical current in the intermediate field superconducting phase.
