Related papers: Two phase transitions in ${(d_{x^2-y^2}+is)}$-wave…
We establish universal behavior in temperature dependencies of some observables in $(s+id)$-wave BCS superconductivity in the presence of a weak $s$ wave. There also could appear a second second-order phase transition. As temperature is…
The temperature dependencies of specific heat and spin susceptibility of a coupled $d_{x^2-y^2} +id_{xy}$ superconductor in the presence of a weak $d_{xy}$ component are investigated in the tight-binding model (1) on square lattice and (2)…
In view of the current interest in d_{x^{2}-y^{2}}+id_{xy} superconductors some of their thermodynamic properties have been studied to obtain relevant information for experimental verification. The temperature dependence of the specific…
We study the phase transition from a $d_{x^2-y^2}$ to $d_{x^2-y^2}+d_{xy}$ superconductor using the tight-binding model of two-dimensional cuprates. As the temperature is lowered past the critical temperature $T_c$, first a $ d_{x^2-y^2}$…
We study the effect of dissipation on quantum phase fluctuations in d-wave superconductors. Dissipation, arising from a nonzero low frequency optical conductivity which has been measured in experiments below $T_c$, has two effects: (1) a…
We present measurements of the superconducting and charge density wave critical temperatures (Tc and TCDW) as a function of pressure in the transition metal dichalchogenides 2H-TaSe2 and 2H-TaS2. Resistance and susceptibility measurements…
We report a detailed analytic and numerical study of electronic thermal conductivity in d-wave superconductors. We compare theory of the cross over at low temperatures from T-dependence to T^3-dependence for increasing temperature with…
Using a mean-field BCS-like approach on the bidimensional extended Hubbard Hamiltonian we calculate the superconducting transition temperature Tc as a function of the hole content nh, for the d-wave and extended-s wave gap symmetries. To…
The temperature and field dependence of the superfluid density $\rho_s$ in the vortex state of a d-wave superconductor are calculated using a microscopic model in the quasiclassical approximation. We show that at temperatures below T^{*}…
The newly discovered BaPt$_2$As$_2$ shows a structural distortion at around 275~K, followed by the emergence of superconductivity at lower temperatures. Here we identify the presence of charge density wave (CDW) order at room temperature…
We present specific heat measurements which show an unexpected phase transition from d-wave symmetry to s-wave symmetry as the temperature is reduced in electron-doped Pr$_{2-x}$Ce$_{x}$CuO$_{4-\delta}$ (PCCO), in both optimal and…
We investigate the behavior of the superconducting transition temperature within a previously developed BCS-Bose Einstein crossover picture. This picture, based on a decoupling scheme of Kadanoff and Martin, further extended by Patton, can…
We study superconductor-ferromagnet bi-layers, not only for s-wave but also for d-wave superconductors. We observe oscillations of the critical temperature when varying the thickness of the ferromagnetic layer for both s-wave and d-wave…
We describe the different regimes of finite temperature dynamics in the vicinity of a zero temperature superconductor to insulator quantum phase transition in two dimensions. New results are obtained for a low temperature phase-only…
The recently proposed theoretical model of superconductors endowed with two distinct superconducting phases and critical temperatures is further analyzed by introducing two distinct order parameters, described by two scalar fields which…
Two correlated superconducting phases are identified in layered superconductor BaTi2(Sb1-xBix)2O (x=0.16), with the superconducting transition temperatures of TC = 6 K (the high TC phase) and 3.4 K (the low TC Phase), respectively. The 6 K…
The superconducting properties of a layered system are analyzed for the cases of zero- and non-zero angular momentum of the pairs. The effective thermodynamic potential for the quasi-2D XY-model for the gradients of the phase of the order…
All the new layer perovskite superconductors seem to show a phenomenon of symmetry mixing with repect to the order parameter. An analysis of the different alternative of mixing and how far could them be presented is carried out. For the…
A stability criterion is worked out for the superconducting phase. The validity of a prerequisite, established previously for persistent currents, is thereby confirmed. Temperature dependence is given for the specific heat and concentration…
Very high energy resolution photoemission experiments on high quality samples of optimally doped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ show new features in the low-energy electronic excitations. A marked change in the binding energy and…