Related papers: Abrupt transition in quasiparticle dynamics at opt…
High-$T_c$ cuprate superconductors are characterized by a strong momentum-dependent anisotropy between the low energy excitations along the Brillouin zone diagonal (nodal direction) and those along the Brillouin zone face (antinodal…
The superconducting phase of the 2D one-band Hubbard model is studied within the FLEX approximation and by using an Eliashberg theory. We investigate the doping dependence of $T_c$, of the gap function $\Delta ({\bf k},\omega)$ and of the…
The doping dependence of the themopower, in-plane resistivity rho_ab(T), out-of-plane resistivity rho_c(T), and susceptibility has been systematically measured for high-quality single crystal Bi2Sr2Ca2Cu3O10+delta. We found that the…
The interplay between the quasi 1-dimensional CuO-chains and the 2-dimensional CuO2 planes of YBa2Cu3O6+x (YBCO) has been in focus for a long time. Although the CuO-chains are known to be important as charge reservoirs that enable…
A systematic analysis of the complex lineshape at $(\pi,0)$ of heavily overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ is presented. We show that a coherent component in the quasi-particle excitation is correlated with the superfluid density…
Superconductivity in cuprates peaks in the doping regime between a metal at high p and an insulator at low p. Understanding how the material evolves from metal to insulator is a fundamental and open question. Early studies in high magnetic…
Bulk superconductor samples of YBa2Cu3-xCoxO7-{\delta} with x = 0, 0.01, 0.03, 0.05 are synthesized by solid-state reaction route. Both x-ray diffraction and electron microscopy have been employed to study the phase identification,…
We report a systematic study of the Nernst effect in films of the electron doped cuprate superconductor La2-xCexCuO4 (LCCO) as a function of temperature and magnetic field (up to 14 T) over a range of doping from underdoped (x=0.08) to…
We report the pressure effect in Bi2Sr2Ca2Cu3O10+{\delta} (Bi-2223) single crystal with a small amount of intergrowth of Bi2Sr2CaCu2O8+{\delta} (Bi-2212). Their superconducting transition temperatures Tcs showed a domelike shape as a…
By substituting Fe with the 5d-transition metal Pt in BaFe2As2, we have successfully synthesized the superconductors BaFe2-xPtxAs2. The systematic evolution of the lattice constants indicates that the Fe ions were successfully replaced by…
We present an exact diagonalization study of the single particle spectral function in the so-called t-t'-t''-J model in 2D. As a key result, we find that unlike the `pure' t-J model, hole doping leads to a major reconstruction of the…
We report characterization results by energy dispersive x-ray analysis and AC-susceptibility for a statistically relevant number of single layer Bi-cuprate single crystals. We show that the two structurally quite different modifications of…
In the physics of condensed matter, quantum critical phenomena and unconventional superconductivity are two major themes. In electron doped cuprates, the low upper critical field allows one to study the putative QCP at low temperature and…
Study and comparison of over 30 examples of electron doped BaFe2As2 for transition metal (TM) = Co, Ni, Cu, and (Co/Cu mixtures) have lead to an understanding that the suppression of the structural/antiferromagnetic phase transition to low…
The compound HgBa$_2$CuO$_{4+\Delta}$ (Hg1201) exhibits a simple tetragonal crystal structure and the highest superconducting transition temperature (T$_c$) among all single Cu-O layer cuprates, with T$_c$ = 97 K (onset) at optimal doping.…
Conductivity due to superconducting fluctuations studied in optimally doped YBa2Cu3O7-d films displays a stronger decay law in temperature than explainable by theory. A formula is proposed, which fits the data very well with two…
We study the reconfiguration of the angular resolved photoemission spectrum near $M$ point which occurs in Bi$_2$Sr$_2$CaCu$_2$O$_8$ upon cooling below the superconducting transition temperature. Restricting our attention to the case of…
In order to explain the emergence of the anomalous pseudogap state and high-temperature superconductivity in the cuprates, intense research activity over three decades has focused on unravelling the connection between the various…
We have investigated the pressure dependence of the superconducting transition temperature $T_{c}$ up to 18 GPa of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ single crystals ranging from the highly underdoped through the nearly optimally…
We show that the unusual doping dependence of the isotope effects on transition temperature and zero temperature in - plane penetration depth naturally follows from the doping driven 3D-2D crossover, the 2D quantum superconductor to…