Related papers: Abrupt transition in quasiparticle dynamics at opt…
We report on the ab-plane reflectance of the high temperature superconductor Bi2Sr2CaCu2O8+d (Bi-2212). Samples spanning the doping range from under doped with Tc = 67 K(UD), to optimally doped with Tc = 96 K (OPT), to over doped with Tc =…
The non-equilibrium state of the high-Tc superconductor Bi2Sr2CaCu2O8+delta and its ultrafast dynamics have been investigated by femtosecond time- and angle-resolved photoemission spectroscopy well below the critical temperature. We probe…
In conventional superconductors, the pairing energy gap (\Delta) and superconducting phase coherence go hand-in-hand. As the temperature is lowered, both the energy gap and phase coherence appear at the transition temperature T_c. In…
We report an ultrafast Time-Resolved Raman scattering study of the out-of-equilibrium photoinduced dynamics across the superconducting to normal state phase transition of the cuprate Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. Using the…
We systematically investigate the photoexcited (PE) quasi-particle (QP) relaxation and low-energy electronic structure in electron doped Ba(Fe_{1-x}Co_{x})_{2}As_{2} single crystals as a function of Co doping, 0<= x <=0.11. The evolution of…
The doping and temperature dependence of the thermodynamic properties in cuprate superconductors is studied based on the kinetic energy driven superconducting mechanism. By considering the interplay between the superconducting gap and…
Although phase diagrams can be leveraged to investigate high transition temperature (high-$T_c$) superconductivity, the issue has not been discussed thoroughly. In this study, we elucidate the phase diagram of the overdoped side of…
The superconducting state is achieved by the condensation of Cooper pairs and is protected by the superconducting gap. The pairing interaction between the two electrons of a Cooper pair determines the superconducting gap function. Thus, it…
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…
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…
I review progress in measurements of the dynamic spin susceptibility in the normal state which yield a new phase diagram and discuss microscopic calculations which yield qualitative, and in many cases, quantitative agreement with the…
The evolution of Ca$_{2-x}$Na$_{x}$CuO$_{2}$Cl$_{2}$ from Mott insulator to superconductor was studied using angle-resolved photoemission spectroscopy. By measuring both the excitations near the Fermi energy as well as non-bonding states,…
We analyze the hole doping mechanism in Bi_2Sr_{2-x}La_xCuO_{6+\delta} (BSLCO). The singular optimum around x=0.35 is found to be connected with a feedback between the doped CuO_2 layers and its dopant reactant [La^{3+}/Bi^{3+}-O_\delta]…
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…
We have conducted a highly precise doping controlled experiment on a thin film of the single layer cuprate Bi2Sr2-xLaxCuOy (x = 0.6), in order to observe the superconducting insulating transition (SIT). Sr2+/La3+ substitution (x = 0.6)…
The condensation of an electron superfluid from a conventional metallic state at a critical temperature $T_c$ is described well by the BCS theory. In the underdoped copper-oxides, high-temperature superconductivity condenses instead from a…
We followed step by step the transition from an antiferromagnetic (AF) Mott insulator to a superconducting (SC) metal in the Bi$_2$Sr$_2$CaCu$_{2}$O$_{8+\delta}$ (Bi-2212) cuprate using the electronic Raman scattering spectroscopy. This was…
The mechanism that controls the superconducting (SC) transition temperature $T_{\mathrm{c}}^{0}$ as a function of doping is one of the central questions in cuprate high-temperature superconductors. While it is generally accepted that…
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 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…