Related papers: Absence of gross inhomogeneity in HTS cuprates
It is well established that the hole density in the prototypical superconductor La$_{2-x}$Sr$_x$CuO$_4$ is very inhomogeneous due to Sr-dopant induced disorder. On the other hand, until recently it is widely believed that the hole…
In the present work, scanning tunneling microscopy/spectroscopy (STM/STS) measurements were carried out on underdoped $\rm Bi_2Sr_{2-{\it x}}La_{\it x}CuO_{6+\delta}$ and $\rm Bi_2Sr_2CaCu_2O_{8+\delta}$ to clarify the origin of the…
We report a set of scanning tunneling microscopy (STM) and spectroscopy (STS) experiments studying native defects in CVT grown 1T-TaS$_2$. Six different sample surfaces from four bulk crystals were investigated. Wide area imaging reveals a…
We have developed a material specific theoretical framework for modelling scanning tunneling spectroscopy (STS) of high temperature superconducting materials in the normal as well as the superconducting state. Results for…
An attempt is made at reconciling the results of the prime experiments on the high temperature superconducting cuprates from Loram et al. and Davis et al. relating to electronic specific heat and to energy-resolved scanning tunnelling…
Using finite size scaling we analyze specific heat and London penetration depth data to estimate the spatial extent of the superconducting grains in so called high-quality Bi2Sr2CaCu2O8+delta single crystals. Contrary to the previously…
We examine the effect on the superconducting transition temperature (Tc) of chemical inhomogeneities in Bi2201 and Bi2212 single crystals. Cation disorder at the Sr crystallographic site is inherent in these materials and strongly affects…
This project sought to consider two important aspects of the planetary nebula NGC 3242 using new long-slit HST/STIS spectra. First, we investigated whether this object is chemically homogeneous by dividing the slit into different regions…
In two-dimensional lattices the electronic levels are unevenly spaced, and the density of states (DOS) displays a logarithmic divergence known as the Van Hove singularity (VHS). This is the case in particular for the layered cuprate…
We report $^{17}$O NMR measurements in single crystals of overdoped Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ with $T_c=82$ K. We measure the full anisotropy of the planar oxygen Knight shift, electric field gradient, and spin lattice relaxation…
Scanning tunneling spectroscopy studies on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ suggest the presence of electronic inhomogeneity with a large spatial variation in gap size. Andersen {\it et al} have modelled this variation by assuming a…
We investigate the influence of inhomogeneity in the pairing coupling constant $U(\vec r)$ on dirty BCS superconductors, focusing on $T_c$, the order parameter $\Delta(\vec r)$, and the energy gap $E_g(\vec r)$. Within mean-field theory, we…
In a recent article, Alldredge et al. reported tunnelling data obtained at T = 4.2 K by STM in Bi-2212 having different doping levels, p, and a new way to fit the measured differential conductances, g(V), which are linearly proportional to…
We use 89Y NMR in $YBa_{2}Cu_{3}O_{6+y}$ in order to evaluate with high sensitivity the distribution of hole content p in the CuO2 planes. For y=1 and y=0.6, this hole doping distribution is found narrow with a full width at half maximum…
We have found a quantitative connection between the evolution of the inhomogeneous nanoscale electronic gaps (INSEG) state detected in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ by scanning tunneling microscopy/spectroscopy (STM/S) and the two…
X-ray scattering measurements on optimally-doped single crystal samples of the high temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ reveal the presence of three distinct incommensurate charge modulations, each involving a…
In cuprate superconductors, the highest $T_c$ is possessed by the HgBa$_2$Ca$_2$Cu$_3$O$_{8+\delta}$ (Hg-1223) system at ambient pressure, but the reason remains elusive. Here we report the scanning tunneling measurements on the Hg-1223…
Scanning Tunneling Spectroscopy on cleaved BSCCO(2212) single crystals reveal inhomogeneities on length-scales of $\sim$30 $\AA$. While most of the surface yields spectra consistent with a d-wave superconductor, small regions show a doubly…
We analyze how the coherence peaks observed in Scanning Tunneling Spectroscopy (STS) of cuprate high temperature superconductors are transferred from the cuprate layer to the oxide layers adjacent to the STS microscope tip. For this…
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…