Related papers: A possible method to confirm $\pm s$-wave pairing …
We study Josephson junctions made of semiconducting nanowires with Rashba spin-orbit coupling, where superconducting correlations are induced by the proximity effect. In the presence of a suitably directed magnetic field, the system…
We report a new class of $c$-axis Josephson tunneling experiments in which a conventional superconductor (Pb) is deposited across a single twin boundary of a YBa_2Cu_3O_{7-\delta} crystal. We measure the critical current as a function of…
We examine a contact between a superconductor whose order parameter changes sign across the Brillioun zone, and an ordinary, uniform-sign superconductor. Within a Ginzburg-Landau type model, we find that if the the barrier between the two…
Junctions and interfaces consisting of unconventional superconductors provide an excellent experimental playground to study exotic phenomena related to the phase of the order parameter. Not only the complex structure of unconventional order…
We present a microscopic theory of dc Josephson current, based on the construction of a coherent temperature Green function in the tight-binding approximation, in junctions with multiband superconductors. This theory is applied to the…
The order parameter of High-T$_{c}$ superconductors through a series of experiments has been quite conclusively demonstrated to not be of the normal $s-wave$ type. It is either a pure $d_{x^{2}-y^{2}}$-wave type or a mixture of a…
Using a simple theoretical model, we demonstrate the emergence of odd-frequency pair amplitudes in conventional Josephson junctions both in the absence of a voltage (DC effect) and in the presence of a finite voltage (AC effect). In both…
We analyze the presence of non-reciprocal critical currents, the so-called superconducting diode effect, in chiral superconductors within a generalized Ginzburg-Landau framework. After deriving its key symmetry conditions we illustrate the…
We report $^{31}$P- and $^{75}$As-NMR studies on (Ca$_4$Al$_2$O$_{6}$)Fe$_2$(As$_{1-x}$P$_x$)$_2$ with an isovalent substitution of P for As. We present the novel evolution of emergent phases that the nodeless superconductivity (SC) in…
Unconventional superconductivity has been predicted to arise in the topologically non-trivial Fermi surface of doped inversion symmetric Weyl semimetals (WSM). In particular, Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) and nodal BCS states are…
Topological superconductors supporting Majorana Fermions with non-abelian statistics are presently a subject of intense theoretical and experimental effort. It has been proposed that the observation of a half-frequency or a fractional…
We discuss the Josephson current between two noncentrosymmetric superconductors. The coexistence of superconducting order parameters between spin-singlet $\Delta_{\text{S}}$ and helical p-wave spin-triplet $\Delta_{\text{T}}$ enriches a…
In high-superconducting transition temperature ($T_{\rm c}$) iron-based superconductors, interband sign reversal ($s_{\rm \pm}$) and sign preserving ($s_{\rm ++}$) $s$-wave superconducting states have been primarily discussed as the…
Superconductivity and magnetism are competing effects that can coexist in certain regimes. Their co-existence leads to unexpected new behaviors that include the onset of exotic electron pair mechanisms and topological phases. In this work,…
We study the impurity scattering on the $\pm$s-wave superconductor, with realistic parameters for the Fe-pnictide superconductors. Using $\mathcal{T}$-matrix method, generalized for the two bands, we found that impurity scattering of the…
We apply the fermion functional renormalization group method to determine the pairing symmetry and pairing mechanism of the FeAs-Based materials. Within a five band model with pure repulsive interactions, we find an electronic-driven…
We formulate a quantum waveguide theory of the Josephson effect in multiband superconductors, with special emphasis on iron-based materials. By generalizing the boundary conditions of the scattering problem, we first determine the Andreev…
Motivated by recent experiments, we investigate Josephson scanning tunneling spectroscopy in an s-wave superconductor. We demonstrate that the spatial oscillations in the superconducting order parameter induced by defects can be spatially…
We show that the two-band nature of noncentrosymmetric superconductors leads naturally to an anomalous Josephson current appearing at zero phase difference in a clean noncentrosymmetric superconductor/ferromagnet/noncentrosymmetric…
An important challenge in condensed matter physics is understanding iron-based superconductors. Among these systems, the iron selenides hold the record for highest superconducting transition temperature and pose especially striking puzzles…