Probing the Phase Diagram of Bi2Sr2CaCu2O8+d with Tunneling Spectroscopy

Abstract

Tunneling measurements are performed on Ca-rich single crystals of Bi2Sr2CaCu2O8+d (Bi2212), with various oxygen doping levels, using a novel point contact method. At 4.2 K, SIN and SIS tunnel junctions are obtained with well-defined quasiparticle peaks, robust dip and hump features and in some cases Josephson currents. The doping dependence of tunneling conductances of Ca-rich Bi2212 are analyzed and compared to stoichiometric Bi2212. A similar profile of energy gap vs. doping concentration is found although the Ca-rich samples have a slighly smaller optimum Tc and therefore smaller gap values for any doping level. The evolution of tunneling conductance peak height to background ratios with hole concentration are compared. For a given doping level, the Ca-rich spectra showed more broadened features compared to the stoichiometric counterparts, most likely due to increased disorder from the excess Ca. Comparison of the dip and hump features has provided some potential insights into their origins.

arXiv comment4 pages, 4 figures; presented at the Applied Superconductivity Conference (August 4-9, 2002) in Houston, TX; to be published in IEEE Trans. Appl. Supercond

References in corpus (8)

• Discovery of microscopic electronic inhomogeneity in the high-Tc superconductor Bi2Sr2CaCu2O8+x
• Electronic Spectra and Their Relation to the (pi,pi) Collective Mode in High-Tc Superconductors
• Signature of Superfluid Density in the Single-Particle Excitation Spectrum of Bi2Sr2CaCu2O8+delta
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• Correlation of Tunneling Spectra in Bi2Sr2CaCu2O(8+delta) with the Resonance Spin Excitation
• Energy gap evolution in the tunneling spectra of Bi2Sr2CaCu2O8+d
• Tunneling Spectroscopy of Overdoped Bi2Sr2CaCu2O8+d Single Crystals
• Slope of the superconducting gap function in $B{i}_{2}S{r}_{2}CaC{u}_2{O}_{8+\delta }$ measured by vacuum tunneling spectroscopy

Cited by in corpus (3)

• From Fermi Arcs to the Nodal Metal: Scaling of the Pseudogap with Doping and Temperature
• Central peak in the pseudogap of high T_c superconductors
• Anisotropic evolution of energy gap in Bi2212 superconductor