Related papers: Superconducting Gap Anisotropy and Quasiparticle I…
With significantly improved sample quality and instrumental resolution, we clearly identify in the (pi,0) ARPES spectra from YBa2Cu3O6.993, in the superconducting state, the long-sought `peak-dip-hump' structure. This advance allows us to…
We calculate the quasiparticle scattering rate in the superconducting state of the overdoped cuprates, in the context of the Eliashberg formalism for a Fermi liquid with strong van Hove singularities close to the chemical potential. For a…
We examine the nature of the collective excitations in a strongly anisotropic system of bosons interacting via Coulomb interaction. Such a system has often been used in the past to model the effects of quantum and classical phase…
We study the interplay of fluctuations and superconductivity in BaFe$_2$As$_2$ (Ba-122) compounds with Ba and Fe substituted by K ($p$ doping) and Co ($n$ doping), respectively. To this end we measured electronic Raman spectra as a function…
Many emergent phenomena appear in doped Mott insulators near the insulator-to-metal transition. In high-temperature cuprate superconductors, superconductivity arises when antiferromagnetic (AFM) order is gradually suppressed by carrier…
Understanding the interplay between magnetism and superconductivity is one of the central issues in condensed matter physics. Such interplay induced nodal structure of superconducting gap is widely believed to be a signature of exotic…
We consider a model of spin-gapped chains weakly coupled by Josephson and Coulomb interactions. Combining such non-perturbative methods as bosonization and Bethe ansatz to treat the intra-chain interactions with the Random Phase…
Underdoped cuprates exhibit a normal-state pseudogap, and their spins and doped carriers tend to spatially separate into 1- or 2-D stripes. Some view these as central to superconductivity, others as peripheral and merely competing. Using…
The 12442 compounds are a recently discovered family of iron-based superconductors, that share several features with the cuprates due to their strongly anisotropic structure, but are so far poorly understood. Here, we report on the gap…
Tunneling measurements have been carried out on heavily underdoped and slightly overdoped Bi2212 single crystals by using a break-junction technique. We find that in-plane tunneling spectra below Tc are the combination of incoherent part…
Scanning tunneling spectroscopy has recently discovered a positive correlation between the magnitude of the superconducting gap and positions of dopant oxygen atoms in Bi-based cuprates. We propose a microscopic mechanism that could be…
Angle-resolved photoemission spectroscopy (ARPES) presents significant simplications in analyzing strictly two-dimensional (2D) materials, but even the most anisotropic physical systems display some residual three-dimensionality. Here we…
The in-plane London penetration depth, $\Delta\lambda(T)$, was measured using a tunnel diode resonator technique in single crystals of Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$ with doping levels $x$ ranging from heavily underdoped, $x$=0.16…
We report the ultra-fast optical response of quasi-particles (QPs) in both the pseudogap (PG) and superconducting (SC) states of underdoped (UD) Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ (Bi2212) single crystal measured with the…
Borocarbide superconductors, which are thought to be conventional BCS-type superconductors, are not so conventional in several electronic Raman properties. Anisotropic gap-like features and finite scattering strength below the gap were…
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…
Ultrafast time-resolved optical spectroscopy in high-temperature superconductors enables the direct real-time measurement of non-equilibrium quasiparticle recombination dynamics. In addition, it also gives detailed information about the…
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 =…
We study models for superconductivity with two interactions: $V^>$ due to antiferromagnetic(AF) fluctuations and $V^<$ due to phonons, in a weak coupling approach to the high temperature superconductivity. The nature of the two interactions…
Within the framework of the kinetic energy driven superconducting mechanism, the effect of the extended impurity scatterers on the quasiparticle transport of cuprate superconductors in the superconducting state is studied based on the nodal…