Related papers: Strong- versus Weak-Coupling Paradigms for Cuprate…
Using a doping-determined multiband model spectrum of a "typical'' cuprate the effective mass of the paired carriers is calculated on the whole doping scale. Large $m_{ab}$ values quench rapidly with leaving the very underdoped region.…
We study a simple BCS-like model which describes unconventional superconductivity on the basis of an electron-electron attraction corresponding to the delta-shell potential: $U(r) = -g \delta(r-r_0)$. It predicts a $T_c$ vs. doping behavior…
The discovery of superconductivity in copper oxide compounds has attracted considerable attention over the past three decades. The high transition temperature in these compounds, exhibiting proximity to an antiferromagnetic order in their…
Starting from a spin-fermion model for the cuprate superconductors, we obtain an effective interaction for the charge carriers by integrating out the spin degrees of freedom. Our model predicts a quantum critical point for the…
We investigated systemically YBa2Cu3-x(Fe, Co, Al, Zn)xO7-{\delta} (x=0.0\sim0.5) cuprates through the XRD, the test of superconductivity, oxygen contents,positron annihilation technology and simulated calculations. The experimental results…
For an electron gas with a $ \delta $-function attraction we investigate the crossover from weak-coupling to strong-coupling superconductivity as well as normal state near the temperature $T^*$, at which the strong coupling produces a…
The c-axis optical conductivity and d.c. resistivity are calculated within the t-J model assuming that the interlayer hopping is incoherent. Use is made of numerical results for spectral functions recently obtained with the…
We propose a possible scenario for the new metallic conductivity of underdoped and optimally doped cuprates. Charge carriers are assumed to be large polarons which form a Fermi-liquid and Cooper-like pairs below a crossover tempurature…
We first present detailed measurements of the rounding behavior around the superconducting transition temperature, $T_c$, of the in-plane electrical conductivity, magnetoconductivity and magnetization, including the low and moderate…
Recent angle-resolved photoemission (ARPES) experiments have indicated that the electronic dispersion in some of the cuprates possesses an extended saddle point near the Fermi level which gives rise to a density of states that diverges like…
Significant progress towards a theory of high-temperature superconductivity in cuprates has been achieved via the study of effective one- and three-band Hubbard models. Nevertheless, material-specific predictions, while essential for…
Pairing states are essential to understanding the underlying mechanisms of high-temperature superconductivity. Here the non-superconducting state in an optimally doped YBa_2 Cu_3 O_(7-{\delta}) film was driven out of equilibrium by an…
The reflectance of high-quality, unpolished single crystals of YBa_2Cu_3O_{6+x}, for the doping range x=0.50 -> 0.95, has been measured with radiation polarized along the c axis from approx 50 cm^{-1} to 5000 cm^{-1} between 10 K and 300 K.…
Superconductivity in doped SrTiO$_3$ has remained an enduring mystery for over 50 years. The material's status as a ``quantum" ferroelectric metal, characterized by a soft polar mode, suggests that quantum criticality could play a pivotal…
A precursor of superconductivity has been searched in the in-plane optical spectra of underdoped YBa$_2$Cu$_3$O$_y$, in which the previous $c$-axis optical spectra showed the presence of superconducting carriers at a temperature far above…
We describe a simple AC susceptometer built in-house that can be used to make high-resolution measurements of the magnetic susceptibility of high-temperature superconductors in an undergraduate physics lab. Our system, cooled using liquid…
Superfluid condensation can fundamentally be different from that predicted by the Bardeen-Cooper-Schrieffer (BCS) theory. In a broad class of low-carrier-density superconductors, such as granular aluminum, doped nitrides, and high-Tc…
In this paper we study an evolution of low-temperature thermodynamical quantities for an electron gas with a $ \delta $-function attraction as the system crosses over from weak-coupling (BCS-type) to strong-coupling (Bose-type)…
Superconducting transition temperature is calculated for differently doped bilayer cuprates. Superexchange is assumed to be the dominating mechanism of high-temperature superconductivity, but the contribution from the phonon potential is…
Due to their proximity to an antiferromagnetic phase and to the mysterious pseudogap, underdoped cuprates have attracted great interest in the high Tc community for many years. A central issue concerns the role of quantum and thermal…