Related papers: Fluctuations and $T_c$ reduction in cuprate superc…
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 report on isofield curves of $\sqrt{-M}$ vs. T, where M is the reversible magnetization, of YBa_2Cu_3O_{6.95}, YBa_2Cu_3O_{6.65}, and Bi_2Sr_2CaCu_2O_{8+x} with the magnetic field, H, applied parallel to the c-axis of the samples (and…
One of the most remarkable properties of the high-temperature superconductors is a pseudogap regime appearing in the underdoped cuprates above the superconducting transition temperature T_c. The pseudogap continously develops out of the…
We first argue that the collective behaviour of the Cooper pairs created by thermal fluctuations well above the superconducting transition temperature, Tc, is dominated by the uncertainty principle which, in particular, leads to a…
Critical fluctuations have been studied in the microwave conductivity of Bi_2Sr_2CaCu_2O_(8+\delta), Bi_2Sr_2Ca_2Cu_3O_(10+delta), and YBa_2Cu_3O_(7-delta) thin films above T_c. It is found that a consistent analysis of the real and…
The thermodynamics of the superconducting transition is studied as a function of doping using high-resolution expansivity data of YBa2Cu3Ox single crystals and Monte-Carlo simulations of the anisotropic 3D-XY model. We directly show that Tc…
Recent Scanning Tunneling Spectra(STS) measurement on underdoped cuprate discovers the increase of the maximum superconducting transition temperature $T_c$ when the size of charge transfer gap (CTG) is reduced. Applying pressure is another…
Phase fluctuations of the superconducting order parameter play a larger role in the cuprates than in conventional BCS superconductors because of the low superfluid density of a doped insulator. In this paper, we analyze an XY model of…
The doping dependence of the superfluid density $\rho_{\text{s}}$ exhibits distinct behaviors in the underdoping and overdoping regimes of the cuprate, while the superconducting (SC) transition temperature $T_c$ generally scales with…
We report on a study of the superconducting order parameter thermodynamic fluctuations in $\mathrm{YBa}_2\mathrm{Cu}_3\mathrm{O}_{7 - \delta}$, $\mathrm{Bi}_{2}\mathrm{Sr}_{2}\mathrm{CaCu}_{2}\mathrm{O}_{8+ \delta}$ and…
We propose a theoretical description of the superconducting state of under- to overdoped cuprates, based on the short coherence length of these materials and the associated strong pairing fluctuations. The calculated $T_c$ and the zero…
If phase coherence determines the superconducting transition temperature Tc in the cuprate oxides, it is of great interest to understand the role that dynamics of the phase fluctuation plays in bringing about depletion of the…
Superconducting fluctuations (SF) in SmFeAsO$_{0.8}$F$_{0.2}$ (characterized by superconducting transition temperature $T_{c} \simeq 52.3$ K) are investigated by means of isothermal high-resolution dc magnetization measurements. The…
In conventional, phonon-mediated superconductors, the transition temperature $T_c$ and normal-state scattering rate $1/\tau$ - deduced from the linear-in-temperature resistivity $\rho(T)$ - are linked through the electron-phonon coupling…
Chain-like structured superconductive materials (such as A_2Cr_3As_3, with A = K, Rb, Cs) exhibit the multiband electronic structure of single-particle states, where coexisting quasi-one-dimensional (Q1D) and conventional higher-dimensional…
The evolution of the temperature dependence of pseudogap $\Delta$*(T) in optimally doped (OD) YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) films with $T_{c}$ = 88.7 K under the influence of a magnetic field $B$ up to 8 T has been studied in detail.…
We report the analysis of fluctuation conductivity (FLC) and pseudogap (D*) in Fe-based superconductor SmFeAsO0.85 with Tc = 55 K derived from resistivity experiments. In the FLC analysis distinct 2D-3D (MT-AL) crossover typical for…
Thermodynamic quantities are derived for superconducting and pseudogap regimes by taking into account both amplitude and phase fluctuations of the pairing field. In the normal (pseudogap) state of the underdoped cuprates, two domains have…
The temperature dependencies of the excess conductivity $\sigma'(T)$ and possible pseudogap (PG), in a Dy$_{0.6}$Y$_{0.4}$Rh$_{3.85}$Ru$_{0.15}$B$_4$ polycrystal were studied for the first time. It was shown that $\sigma'(T)$ near T$_{c}$…
The low-energy electronic excitation spectrum and gap structure in optimally doped and overdoped Y_{1-x}Ca_{x}Ba_{2}Cu_{3}O_{7-\delta} single crystals are investigated by real-time measurements of the quasiparticle relaxation dynamics with…