174 citations · 990 across the 36 of their papers we have counts for
36 papers
Electromagnetic response of spinful Majorana fermions
Shingo Kobayashi, Masatoshi Sato
A remarkable feature of topological superconductors is the emergence of Majorana fermions in electron systems. Whereas the emergent Majorana fermions share the self-anti-particle p…
Discontinuous Transition to Superconducting Phase
Takumi Sato, Shingo Kobayashi, Yasuhiro Asano
We discuss the instability of uniform superconducting states that contain the pairing correlations belonging to the odd-frequency symmetry class. The instability originates from th…
Crystal-symmetry-protected gapless vortex-line phases in superconducting Dirac semimetals
Shingo Kobayashi, Shuntaro Sumita, Motoaki Hirayama +1
Vortex lines in superconducting Dirac semimetals realize crystal-symmetry-protected gapless vortex-line phases in which gapless excitations propagate inside a vortex line, in the p…
Nuclear spin relaxation rate of nonunitary Dirac and Weyl superconductors
Koki Maeno, Yuki Kawaguchi, Yasuhiro Asano +1
Nonunitary superconductivity has attracted renewed interest as a novel gapless phase of matter. In this study, we investigate the superconducting gap structure of nonunitary odd-pa…
Nuclear and magnetic spin structure of the antiferromagnetic triangular lattice compound LiCrTe investigated by SR as well as neutron and X-ray diffraction
E. Nocerino, C. Witteveen, S. Kobayashi +12
Twodimensional (2D) triangular lattices antiferromagnets (2DTLA) often manifest intriguing physical and technological properties, due to the strong interplay between lattice…
Spin Susceptibility of a J=3/2 Superconductor
Dakyeong Kim, Takumi Sato, Shingo Kobayashi +1
We discuss the spin susceptibility of superconductors in which a Cooper pair consists of two electrons having the angular momentum J=3/2 due to strong spin-orbit interactions. The…
Bogoliubov Fermi surfaces from pairing of emergent fermions on the pyrochlore lattice
Shingo Kobayashi, Ankita Bhattacharya, Carsten Timm +1
We examine the appearance of superconductivity in the strong-coupling limit of the Hubbard model on the pyrochlore lattice. We focus upon the limit of half filling, where the norma…
Quasiparticle on Bogoliubov Fermi Surface and Odd-Frequency Cooper Pair
Dakyeong Kim, Shingo Kobayashi, Yasuhiro Asano
We discuss a close relationship between a quasiparticle on the Bogoliubov Fermi surface and an odd-frequency Cooper pair in a superconductor in which a Cooper pair consisting of tw…
Possible topological phases in quantum anomalous Hall insulator/unconventional superconductor hybrid systems
Ryoi Ohashi, Shingo Kobayashi, Yukio Tanaka
Quantum anomalous Hall insulator (QAH)/-wave superconductor (SC) hybrid systems are known to be an ideal platform for realizing two-dimensional topological superconductors with…
Fragile topological insulators protected by rotation symmetry without spin-orbit coupling
Shingo Kobayashi, Akira Furusaki
We present a series of models of three-dimensional rotation-symmetric fragile topological insulators in class AI (time-reversal symmetric and spin-orbit-free systems), which have g…
Electric Multipoles of Double Majorana Kramers Pairs
Yuki Yamazaki, Shingo Kobayashi, Ai Yamakage
A single Majorana Kramers pair hosts only one component of the magnetic multipole. This can be used to determine the bulk Cooper-pair symmetry through surface-sensitive spectroscop…
Josephson effect of superconductors with electrons
Dakyeong Kim, Shingo Kobayashi, Yasuhiro Asano
The angular momentum of an electron is characterized well by pseudospin with in the presence of strong spin-orbit interactions. We study theoretically the Josephson effect…
Majorana multipole response: General theory and application to wallpaper groups
Shingo Kobayashi, Yuki Yamazaki, Ai Yamakage +1
Whereas identification of Cooper pair symmetry is the first and crucial step in the investigation of unconventional superconductors, only a few have been established so far because…
Magnetic response of Majorana Kramers pairs with an order-two symmetry
Yuki Yamazaki, Shingo Kobayashi, Ai Yamakage
We study an intrinsic relation between the topology of bulk electronic states and magnetic responses of Majorana Kramers pairs, Kramers pairs of Majorana fermions, on a surface of…
Double Majorana vortex zero modes in superconducting topological crystalline insulators with surface rotation anomaly
Shingo Kobayashi, Akira Furusaki
The interplay of time-reversal and -fold rotation symmetries () is known to bring a new class of topological crystalline insulators (TCIs) having surface Dirac cone…
Nodal Andreev Spectra in Multi-Majorana Three-Terminal Josephson Junctions
Keimei Sakurai, Maria Teresa Mercaldo, Shingo Kobayashi +6
We investigate the Andreev-bound-state (ABS) spectra of three-terminal Josephson junctions which consist of 1D topological superconductors (TSCs) harboring multiple zero-energy edg…
Magnetic Response of Majorana Kramers Pairs Protected by Z2 Invariants
Yuki Yamazaki, Shingo Kobayashi, Ai Yamakage
On the surface of time-reversal-invariant topological superconductors, Kramers pairs of Majorana fermions with chiral and crystalline symmetries exhibit completely uniaxial or octu…
Generalized Berry phase for a bosonic Bogoliubov system with exceptional points
Terumichi Ohashi, Shingo Kobayashi, Yuki Kawaguchi
We discuss the topology of Bogoliubov excitation bands from a Bose-Einstein condensate in an optical lattice. Since the Bogoliubov equation for a bosonic system is non-Hermitian, c…
Majorana multipole response of topological superconductors
Shingo Kobayashi, Ai Yamakage, Yukio Tanaka +1
In contrast to elementary Majorana particles, emergent Majorana fermions (MFs) in condensed-matter systems may have electromagnetic multipoles. We developed a general theory of mag…
Topological Crystalline Materials of Electrons: Antiperovskites, Dirac points, and High Winding Topological Superconductivity
Takuto Kawakami, Tetsuya Okamura, Shingo Kobayashi +1
We present a theory of the high-spin generalization of topological insulators and their doped superconducting states. The higher-spin topological insulators involve a pair of $J=3/…
Symmetry conditions of a nodal superconductor for generating robust flat-band Andreev bound states at its dirty surface
Satoshi Ikegaya, Shingo Kobayashi, Yasuhiro Asano
We discuss the symmetry property of a nodal superconductor that hosts robust flat-band zero-energy states at its surface under potential disorder. Such robust zero-energy states ar…
Symmetry-protected line nodes and Majorana flat bands in nodal crystalline superconductors
Shingo Kobayashi, Shuntaro Sumita, Youichi Yanase +1
Line nodes in the superconducting gap are known to be a source of Majorana flat bands (MFBs) in time-reversal-invariant superconductors (SCs). Here, we extend this relation to all…
Crossing-Line-Node Semimetals: General Theory and Application to Rare-Earth Trihydrides
Shingo Kobayashi, Youichi Yamakawa, Ai Yamakage +3
Multiple line nodes in energy-band gaps are found in semimetals preserving mirror-reflection symmetry. We classify possible configurations of multiple line nodes with crossing poin…
Anisotropic magnetic responses of topological crystalline superconductors
Yuansen Xiong, Ai Yamakage, Shingo Kobayashi +2
Majorana Kramers pairs emerged on surfaces of time-reversal-invariant topological crystalline superconductors show the Ising anisotropy to an applied magnetic field. We clarify tha…