Starting from a uniform d-wave superconducting phase we study the energy cost due to imposed unidirectional defects with a vanishing pairing amplitude. Both renormalized mean-field theory and variational Monte Carlo calculations within the t–J model yield that the energies of inhomogeneous and uniform phases are very close to each other. This suggests that small perturbations in the microscopic...

We review and extend some results for a generalized Ginzburg-Landau energy functional, introduced in the physics literature to model composite superconducting/normal body. In this formulation, the order parameter is defined everywhere in the composite system, with the intention to capture the effect of superconducting electrons pairs diffusing in the normal parts. For suitable choices of the ma...

Iron chalcogenide superconductors have become one of the most investigated superconducting materials in recent years due to high upper critical fields, competing interactions and complex electronic and magnetic phase diagrams. The structural complexity, defects and atomic site occupancies significantly affect the normal and superconducting states in these compounds. In this work we review the v...

We study the influence of Casimir energy on the critical field of a superconducting film, and we show that by this means it might be possible to directly measure, for the first time, the variation of Casimir energy that accompanies the superconducting transition. It is shown that this novel approach may also help clarifying the long-standing controversy on the contribution of TE zero modes to t...

We study the influence of Casimir energy on the critical field of a superconducting film, and we show that by this means it might be possible to directly measure, for the first time, the variation of Casimir energy that accompanies the superconducting transition. It is shown that this novel approach may also help clarifying the long-standing controversy on the contribution of TE zero modes to t...

The recently discovered ruthenocuprates have attracted great interest because of the microscopic coexistence of superconducting and ferromagnetic order. Typically, these materials become magnetically ordered at temperatures around 125-145K and superconductivity sets in between 15 and 50K. While superconductivity arises in the CuO2 layers the RuO2 layers in between order magnetically. In this pa...

The low-energy electronic structure of the nearly optimally doped trilayer cuprate superconductor Bi(2)Sr(2)Ca(2)Cu(3)O(10+delta) is investigated by angle-resolved photoemission spectroscopy. The normal state quasiparticle dispersion and Fermi surface and the superconducting d-wave gap and coherence peak are observed and compared with those of single- and bilayer systems. We find that both the ...

Proximity to a superconductor is predicted to induce exotic quantum phases in topological insulators. Here, scanning superconducting quantum interference device (SQUID) microscopy reveals that aluminum superconducting rings with topologically insulating Bi2Se3 junctions exhibit a conventional, nearly sinusoidal 2π-periodic current-phase relations. Pearl vortices occur in longer junctions, indic...

The recent discovery of intercalated iron-selenide superconductors [1] has stirred up the condensed-matter community accustomed to the proximity of the superconducting and magnetic phases in various cuprate and pnictide superconductors. Never before has a superconducting state with a transition temperature as high as 30 K been found to coexist with such an exceptionally strong antiferromagnetis...