678 citations · 2.6k across the 62 of their papers we have counts for
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Bogoliubov flat bands in twisted layered materials
Keiji Yada, Yuri Fukaya, Yukio Tanaka
Flat bands have attracted considerable interest in condensed matter physics because they provide a fertile platform for realizing strongly correlated and topological quantum phases…
-wave superconductivity and Josephson current in -wave unconventional magnet/-wave superconductor hybrid systems
Yuri Fukaya, Keiji Yada, Yukio Tanaka
We study the surface density of states in -wave unconventional magnet-spin-singlet -wave superconductor hybrid systems (-wave unconventional magnetic superconductors). Owi…
Crossed surface flat bands in three-dimensional superconducting altermagnets
Yuri Fukaya, Bo Lu, Keiji Yada +2
Superconducting altermagnets have proven to be a promising ground for emergent phenomena, but their study has involved two-dimensional systems. In this work, we investigate three-d…
Engineering subgap states in superconductors by the symmetry of altermagnetism
Bo Lu, Phillip Mercebach, Pablo Burset +4
Combining superconducting and magnetic materials is a promising path to generate exotic interface subgap states. In this regard, altermagnetism is particularly interesting because…
The Josephson effect in Fibonacci superconductors
Ignacio Sardinero, Jorge Cayao, Keiji Yada +2
We theoretically investigate the Josephson effect between two proximized Fibonacci quasicrystals. A quasiperiodic modulation of the chemical potential on a superconducting substrat…
Tunneling conductance in superconducting junctions with -wave unconventional magnets breaking time-reversal symmetry
Yuri Fukaya, Keiji Yada, Yukio Tanaka
A new type of magnet called -wave unconventional magnet is proposed, stimulated by the discovery of altermagnet. We study the tunneling conductance of -wave unconventional ma…
Superconducting phenomena in systems with unconventional magnets
Yuri Fukaya, Bo Lu, Keiji Yada +2
In this work we review the recent advances on superconducting phenomena in junctions formed by superconductors and unconventional magnets. Conventional magnets, such as ferromagnet…
Classification of pair symmetries in superconductors with unconventional magnetism
Kazuki Maeda, Yuri Fukaya, Keiji Yada +3
We consider unconventional magnets with proximity-induced superconductivity and investigate the emergence of superconducting correlations by carrying out a full classification of a…
Josephson effect and odd-frequency pairing in superconducting junctions with unconventional magnets
Yuri Fukaya, Kazuki Maeda, Keiji Yada +3
We consider Josephson junctions formed by coupling two conventional superconductors via an unconventional magnet and investigate the formation of Andreev bound states, their impact…
Evaluation of Doppler shifts in -wave superconductor tunneling junctions
Takashi Sakamori, Kenki Matsuoka, Mitsuhiro Teshigawara +4
The energy levels of quasiparticles in superconductors experience Doppler shifts due to the influence of a finite current flow. The influence of the Doppler shift is particularly p…
Josephson junction induced by altermagnetism
Bo Lu, Kazuki Maeda, Hiroyuki Ito +2
We study the Josephson effect in a superconductor/altermagnet/superconductor (S/AM/S) junction. We find anomalous phenomena including - transition as well as multi-nodal curr…
Theory of Tunneling Spectroscopy in Unconventional -wave Magnet-Superconductor Hybrid Structures
Kazuki Maeda, Bo Lu, Keiji Yada +1
We theoretically study the tunneling conductance of a junction consisting of a two-dimensional unconventional -wave magnet (UPM) and a superconductor (SC) for various pairing sy…
Theory of Josephson current on a lattice model of grain boundary in -wave superconductors
Takashi Sakamori, Satoshi Kashiwaya, Rikizo Yano +3
Identifying the origins of suppression of the critical current at grain boundaries of high-critical-temperature superconductors, such as cuprates and iron-based superconductors, is…
Topological superconductivity in helical crystals
Soma Yoshida, Keiji Yada, Yukio Tanaka +1
We study superconductivity and surface Andreev bound states in helical crystals. We consider the interlayer pairings along the helical hopping and investigate the surface local den…
Particle-hole spectral asymmetry at the edge of multiorbital noncentrosymmetric superconductors
Yuri Fukaya, Keiji Yada, Yukio Tanaka +2
Bogoliubov quasiparticles are a coherent electron-hole quantum superposition which typically, for time-reversal symmetric superconductors, exhibit a spectral distribution with part…
Odd-frequency pairs and anomalous proximity effect in nematic and chiral states of superconducting topological insulators
Takeshi Mizushima, Shun Tamura, Keiji Yada +1
We investigate emergent odd-frequency pairs and proximity effect in nematic and chiral states of superconducting topological insulators (STIs), such as BiSe ( Cu,…
Anomalous Josephson Coupling and High-Harmonics in Non-Centrosymmetric Superconductors with -wave Spin-Triplet Pairing
Yuri Fukaya, Yukio Tanaka, Paola Gentile +2
We study the Josephson effects arising in junctions made of non-centrosymmetric superconductors with spin-triplet pairing having -wave orbital-singlet symmetry. We demonstrate t…
Spin susceptibility for orbital-singlet Cooper pair in the three-dimensional SrRuO superconductor
Yuri Fukaya, Tatsuki Hashimoto, Masatoshi Sato +2
We study the spin susceptibility of the orbital-singlet pairings, including the spin-triplet/orbital-singlet/-wave representation proposed by Suh \textit{et al}., [H.\ G.\…
Theory of pair density wave on a quasi-one-dimensional lattice in the Hubbard model
Soma Yoshida, Keiji Yada, Yukio Tanaka
In this study, we examine the superconducting instability of a quasi-one-dimensional lattice in the Hubbard model based on the random-phase approximation (RPA) and the fluctuation…
Orbital tunable 0- transitions in Josephson junctions with noncentrosymmetric topological superconductors
Yuri Fukaya, Yada Keiji, Yukio Tanaka +2
We investigate the Josephson transport properties in a Josephson junction consisting of a conventional -wave superconductor coupled to a multi-orbital noncentrosymmetric superco…
Identification of Spin-Triplet Superconductivity through a Helical-Chiral Phase Transition in SrRuO Thin-Films
S. Ikegaya, K. Yada, Y. Tanaka +3
Despite much effort for over the two decades, the paring symmetry of a SrRuO superconductor has been still unclear. In this Rapid Communication, motivated by the recent rap…
Time-Reversal Invariant Superconductivity of SrRuO Revealed by Josephson Effects
Satoshi Kashiwaya, Kohta Saitoh, Hiromi Kashiwaya +5
SrRuO is one of the most promising candidates of a topological superconductor with broken time-reversal symmetry, because a number of experiments have revealed evidence…
Theory of Tunneling Effect in 1D AIII-class Topological Insulator (Nanowire) Proximity Coupled with a Superconductor
Ryoi Ohashi, Yukio Tanaka, Keiji Yada
We study the tunneling effect in an AIII-class insulator proximity coupled with a spin-singlet -wave superconductor, in which three phases are characterized by the integer topol…
Spin-Orbital Hallmarks of Unconventional Superconductors Without Inversion Symmetry
Yuri Fukaya, Shun Tamura, Keiji Yada +3
The spin-orbital polarization of superconducting excitations in momentum space is shown to provide distinctive marks of unconventional pairing in the presence of inversion symmetry…