相关论文: Frustration in d-wave Superconducting Circuits: $\…
We explore edge currents in heterostructures formed of a high-$T_c$ cuprate and a conventional $s$-wave superconductors. The resulting $d\pm is$ superconductor spontaneously breaks time reversal symmetry and, remarkably, exhibits large edge…
A boundary between two d-wave superconductors or an s-wave and a d-wave superconductor generally breaks time-reversal symmetry and can generate spontaneous currents due to proximity effect. On the other hand, surfaces and interfaces in…
Loop current order has been reported in the pseudogap regime of a few cuprate systems in polarized neutron scattering experiments. Here we study several observable consequences of such order in the d-wave superconducting state at low T. The…
A formula of the spin current in mesoscopic superconductors is derived from the mean-field theory of superconductivity. The spin flow is generated by the spatial fluctuations of $\vec{d}$ which represents a spin state of spin-triplet…
We discuss an idea to realize a spontaneous current in a superfluid Fermi gas. When a polarized Fermi superfluid ($N_\up > N_\dwn$, where $N_\sigma$ is the number of atoms in the hyperfine state described by pseudospin $\sigma=\uparrow,…
We revisit the supercurrent generation mechanism for superconductors whose superconducting transition temperature are explained by the BCS theory, motivated by the reexamination of the ac Josephson effect [J. Supercond. Nov. Magn. (2015)…
It has previously been found that a magnetic impurity in a conventional $s$-wave superconductor can give rise to a local $\pi$-phase shift of the superconducting order parameter. By studying a finite wire of ferromagnetic impurities, we are…
In a ring of s-wave superconducting material the magnetic flux is quantized in units of $\Phi_0 = \frac{h}{2e}$. It is well known from the theory of Josephson junctions that if the ring is interrupted with a piece of d-wave material, then…
Superconductors separated by a thin tunneling barrier exhibit the Josephson effect that allows charge transport at zero voltage, typically with no phase shift between the superconductors in the lowest energy state. Recently, Josephson…
We study Josephson couplings in unconventional superconductors and generalize the Sigrist-Rice formula by incorporating symmetry constraints and interface orientation disorder. Applying this framework to granular superconducting rings, we…
We consider a one-dimensional superconducting wire where the total number of electrons can be controlled in the Coulomb blockade regime. We predict that a pi soliton (kink) will spontaneously form in the system when the number of electron…
Recently, a theoretical study [Li {\it et al.},~npj Quantum Materials 6, 36 (2021)] investigated a model of a disordered $d$-wave superconductor, and reported local time-reversal symmetry breaking current loops for sufficiently high…
The induction of an s-wave component in a d-wave superconductor is considered. Near the {110}-oriented edges of such a sample, the induced s-wave order parameter together with d-wave component forms a complex combination d+e^{i\phi} s,…
Proximity effects between ferromagnets (F) and superconductors (S) with broken time-reversal symmetry (T) are studied theoretically. For the S side we consider a chiral (p_x \pm ip_y)-wave, and a d_{x^2-y^2}-wave superconductor, the latter…
A superconducting ring with a pi junction made from superconductor/ferromagnetic-metal/superconductor (S-FM-S) exhibits a spontaneous current without an external magnetic field in the ground state. Such pi ring provides so-called quiet…
We study the properties of a quantum impurity embedded in a superconducting host of a d-wave symmetry. The superconductor is described by the extended negative $U$ Hubbard model while the impurity introduces a repulsive interaction to the…
By solving the Bogoliubov - de Gennes equation self-consistently in the presence of a non-equilibrium quasi-particle distribution, we compute the current-voltage characteristic of a phase coherent superconducting island with a tunnel…
We present an experimental review of the nature of the pseudogap in the cuprate superconductors. Evidence from various experimental techniques points to a common phenomenology. The pseudogap is seen in all high temperature superconductors…
The properties of one-dimensional superconductors are strongly influenced by topological fluctuations of the order parameter, known as phase slips, which cause the decay of persistent current in superconducting rings and the appearance of…
New effects in the frustrated transverse Ising ring are predicted. The system is solved based on a mapping of Pauli spin operators to the Jordan-Wigner fermions. We group the low-lying energy levels into bands after imposing appropriate…