Related papers: Atomic manipulation of the gap in Bi$_{2}$Sr$_{2}$…
The cuprate superconductors distinguish themselves from the conventional superconductors in that a small variation in the carrier doping can significantly change the superconducting transition temperature (T_c), giving rise to a…
In cuprate superconductors, the doping of carriers into the parent Mott insulator induces superconductivity and various other phases whose characteristic temperatures are typically plotted versus the doping level $p$. In most materials, $p$…
By systematic chemical substitution of Pt and Ni in the newly-discovered superconductor Nb$_2$PdS$_5$ ($T_c\sim$6 K), we study the evolution of its superconducting properties with doping, focussing on the behavior of the upper critical…
The energy gap of optimally doped Bi2(Sr,R)2CuOy (R=La and Eu) was probed by angle resolved photoemission spectroscopy (ARPES) using a vacuum ultraviolet laser (photon energy 6.994 eV) or He I resonance line (21.218 eV) as photon source.…
We measured the in-plane optical conductivity of a nearly optimally doped (Ba,K)Fe2As2 single crystal with Tc = 39.1 K. Upon entering the superconducting state the optical conductivity below ~20 meV vanishes, strongly suggesting a fully…
The maximum value of the energy gap $\Delta\simeq 8\ meV$ and the ratio $2\delta/kT_c\simeq~2.5$ are determined for a high-temperature superconductor $\rm Bi_2Sr_2CaCu_2O_{8+y}$ by using point contacts. It was found that the…
We have investigated the optimally doped tri-layer cuprate Bi$_2$Sr$_2$Ca$_2$Cu$_3$O$_{10+\delta}$ (Bi2223) by angle-resolved photoemission spectroscopy, and observed energy bands and Fermi surfaces originated from the outer and inner…
We perform a detailed study of temperature, bias and doping dependance of interlayer transport in the layered high temperature superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. We observe that the shape of interlayer characteristics in…
Recent experiments on Bi-based cuprate superconductors have revealed an unexpected enhancement of the pairing correlations near the interstitial oxygen dopant ions. Here we propose a possible mechanism -- based on local screening effects --…
The effect of hydrostatic pressure up to 2 GPa on the superconductiong transitions in La{2-x}Sr{x}CuO{4+delta} is investigated. The ambient and high pressure properties of two series of samples with x=0 and x=0.015 and 0<delta<0.1 are…
A microscopic theory is presented for the observed electronic disorder in superconducting Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. The essential phenomenology is shown to be consistent with the existence of two types of interstitial oxygen…
Superconductivity in high temperature superconductors is achieved by introducing charge carriers into cuprate insulators containing CuO$_2$ planes. Perturbation in these CuO$_2$ planes suppresses superconductivity by strongly affecting the…
As a typical hole-doped cuprate superconductor, Bi 2 Sr 2 CaCu 2 O 8+{\delta} (Bi2212) carrier doping is mostly determined by its oxygen content. Traditional doping methods can regulate its doping level within the range of hole doping. Here…
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…
Recently, scanning tunneling microscopy on Bi-2212 cuprate superconductor has revealed a spatial variation of the energy gap that is directly correlated with a modulation of the apical oxygen position. We identify two mechanisms by which…
Fluctuating superconductivity - vestigial Cooper pairing in the resistive state of a material - is usually associated with low dimensionality, strong disorder or low carrier density. Here, we report single particle spectroscopic,…
The search for a two-dimensional material that simultaneously fulfills some properties for its use in spintronics and optoelectronics, i.e., a suitable bandgap with high in-plane carrier mobility and good environmental stability, is 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…
We show that the doping-controlled superconductor-insulator transition (SIT) in a high critical temperature cuprate system (Bi2Sr2-xLaxCaCu2O8+delta) exhibits a fundamentally different behavior than is expected from conventional SIT. At the…
The tunneling spectra of high temperature superconductors on Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ (Bi-2212) reproducibly show a high bias structure in the form of a dip-hump at voltages higher than the gap voltage. Of central concern is…