Related papers: Multiple-pseudogap phases in hydrogen-doped LaFeAs…

High magnetic fields have revealed a surprisingly small Fermi-surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A…

Close to optimal doping, the copper oxide superconductors show 'strange metal' behavior, suggestive of strong fluctuations associated with a quantum critical point. Such a critical point requires a line of classical phase transitions…

Single crystals of (Ca1-xLax)10(Pt3As8)(Fe2As2)5 (x = 0 to 0.182) superconductors have been grown and characterized by X-ray, microprobe, transport and thermodynamic measurements. Features in the magnetic susceptibility, specific heat and…

We present a study of the structural and physical properties of directly hole doped LaFe1-xMnxAsO (x = 0.0-0.2) and the influence of charge compensation / electron-doping by additional F doping in LaFe0.9Mn0.1AsO1-yFy (y = 0.1-0.5). High…

The specific heat $C$ of the single-layer cuprate superconductor HgBa$_2$CuO$_{4 + \delta}$ was measured in an underdoped crystal with $T_{\rm c} = 72$ K at temperatures down to $2$ K in magnetic fields up to $35$ T, a field large enough to…

Here we establish a more complete phase diagram for FeSe system, based on experimental results of nonstoichiometric Fe1-xSe single crystals that we have developed recently, as well as nearly stoichiometric FeSe single crystals. The…

The pseudogap phenomena in High-$T_{{\rm c}}$ cuprates are investigated on the basis of the Hubbard model which includes only the on-site repulsive interaction $U$. We consider the pairing scenario for the pseudogap. The pseudogap arises…

To investigate the relationship between the pseudogap and superconductivity, we measured both the in-plane ($\rho_{ab}$) and out-of-plane ($\rho_c$) resistivity for oxygen-controlled Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ single crystals…

A major impediment to solving the problem of high-$T_c$ superconductivity is the ongoing confusion about the magnitude, structure and doping dependence of the superconducting gap, $\Delta_0$, and of the mysterious pseudogap found in…

The pseudogap phenomenology is one of the enigmas of the physics of high-Tc superconductors. Many members of the cuprate family have now been characterized with high resolution in both real and momentum space, which revealed highly…

We use angle-resolved photoemission spectroscopy applied to deeply underdoped cuprate superconductors Bi2Sr2(Ca,Y)Cu2O8 (Bi2212) to reveal the presence of two distinct energy gaps exhibiting different doping dependence. One gap, associated…

Temperature-dependent inter-plane resistivity, $\rho_c(T)$, was measured systematically as a function of transition metal substitution in the iron-arsenide superconductors Ba(Fe$_{1-x}$T$_x$)$_2$As$_2$, $T$= Ni, Pd, Rh. The data are…

The paper compares the K-dependence of the superconducting gap in different doping ranges. The fine behavior of the leading edge gap indicates that the pairing susceptibility is peaked at special regions on the Fermi surface. These hot…

The temperature and magnetic field dependence of the in-plane thermal conductivity $\kappa$ of the iron-arsenide superconductor Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ was measured down to $T \simeq 50$ mK and up to $H = 15$ T as a function of Co…

In this paper, we review some of our ARPES results on the superconducting and pseudo gaps in Bi2Sr2CaCu2O8+x. We find that optimally and overdoped samples exhibit a d-wave gap, which closes at the same temperature, Tc, for all k points. In…

By means of oxide molecular beam epitaxy with shutter-growth mode, we have fabricated a series of electron-doped (Sr1-xLax)2IrO4(001)(x = 0, 0.05, 0.1 and 0.15) single crystalline thin films and then investigated the doping dependence of…

The impact of the normal-state pseudogap, present in all optimal and underdoped HTS cuprates, on critical currents and critical temperature is surveyed. With the opening of the pseudogap around a doping state of p=0.19 the condensation…

Heat transport in the cuprate superconductors YBa$_2$Cu$_3$O$_{y}$ and La$_{2-x}$Sr$_x$CuO$_4$ was measured at low temperatures as a function of doping. A residual linear term kappa_{0}/T is observed throughout the superconducting region…

One of the most widely discussed features of the cuprate high Tc superconductors is the presence of a pseudogap in the normal state. Recent transport and specific heat measurements have revealed an abrupt transition at the pseudogap…

The relationship between the pseudogap and superconductivity remains a central puzzle in the physics of cuprates. Hydrostatic pressure provides a clean tuning parameter free from chemical disorder, yet probing the microscopic energy scales…