Temperature dependence of the bulk energy gap in underdoped Bi-2212: Evidence for the mean-field superconducting transition

Abstract

Understanding of the puzzling phenomenon of high temperature superconductivity requires reliable spectroscopic information about temperature dependence of the bulk electronic density of states. Here I present a comprehensive analysis of $T-$evolution of bulk electronic spectra in Bi-2212 obtained by Intrinsic Tunneling Spectroscopy on small mesa structures. Unambiguous spectroscopic information is obtained by obviation of self-heating problem and by improving the spectroscopic resolution. The obtained data indicate that the superconducting transition maintains the mean-field character down to moderate underdoping, and is associated with an abrupt opening of the superconducting gap, which is well described by the conventional BCS $T-$dependence. The mean-field critical temperature reaches maximum at the optimal doping and decreases with underdoping. Such behavior is inconsistent with theories assuming intimate connection between superconducting and antiferromagnetic spin gaps, and support proposals associating high temperature superconductivity with the presence of competing ground states and a quantum critical point near optimal doping.

17 pages, 16 figures

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• A single intrinsic Josephson junction with double-sided fabrication technique
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• Pseudogap Behavior Revealed in Interlayer Tunneling in Overdoped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+x}$

Cited by in corpus (14)

• Pseudogap from ARPES experiment: three gaps in cuprates and topological superconductivity
• THz emission from intrinsic Josephson junctions at zero magnetic field via breather auto-oscillations
• THz emission from a stacked coherent flux-flow oscillator: non-local radiative boundary conditions and the role of geometrical resonances
• Superconducting THz sources with 12% power efficiency
• Observation of superluminal geometrical resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions
• Stabilization of in-phase fluxon state by geometrical confinement in small Bi-2212 mesa structures
• Disparity of superconducting and pseudogap scales in low-Tc Bi-2201 cuprates
• Observation of polaritons in Bi2Sr2CaCu2O8+x single crystals
• Design aspects of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ THz sources: optimization of thermal and radiative properties
• Low anisotropy of the upper critical field in a strongly anisotropic layered cuprate: Evidence for paramagnetically limited superconductivity
• Persistent electrical doping of Bi2Sr2CaCu2O8+x mesa structures
• Strong polaritonic interaction between flux-flow and phonon resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions: Angular dependence and the alignment procedure
• Cascade switching current detectors based on arrays of Josephson junctions
• Tunneling spectra of unconventional quasi-two-dimensional superconductors