Observation of two distinct pairs fluctuation lifetimes and supercurrents in the pseudogap regime of cuprate junctions

Abstract

Pairs fluctuation supercurrents and inverse lifetimes were measured on epitaxial c-axis junctions of the cuprates in the pseudogap regime, with a $PrB{a}_{2}C{u}_3{O}_{7-\delta }$ barrier sandwiched in between two $YB{a}_{2}C{u}_3{O}_{7-\delta }$ or doped $YB{a}_{2}C{u}_3{O}_y$ electrodes, with or without magnetic fields parallel to the a-b planes. All junctions had a ${\mathrm{T}}_{\mathrm{c}}(\mathrm{high})\approx 85-90$ K and a ${\mathrm{T}}_{\mathrm{c}}(\mathrm{low})\approx 50-55$ K electrodes, allowing us to study pairs fluctuation supercurrents and inverse life times in between these two temperatures. In junctions with a pseudogap electrode under zero field, an excesss current due to pair fluctuations was observed which persisted at temperatures above ${\mathrm{T}}_{\mathrm{c}}(\mathrm{low})$, in the pseudogap regime, and up to about ${\mathrm{T}}_{\mathrm{c}}(\mathrm{high})$. No such excess current was observed in junctions without a pseudo-gap in the electrode. The measured conductance spectra at temperatures above ${\mathrm{T}}_{\mathrm{c}}(\mathrm{low})$ were fitted using a modified fluctuations model by Scalapino [Phys. Rev. Lett. \textbf{24}, 1052(1970)] of a junction with a serial resistance. We found that in the pseudo-gap regime, the conductance vs voltage consists of a narrow peak sitting on top of a very broad peak. This yielded two distinct pairs fluctuation lifetimes in the pseudogap electrode which differ by an order of magnitude up to about ${\mathrm{T}}_{\mathrm{c}}(\mathrm{high})$. Under in-plane fields, these two lifetime values remain separated in two distinct groups, which varied with increasing field moderately. We also found that detection of Amperian pairing [Phys. Rev. X \textbf{4}, 031017 (2014)] in our cuprate junctions is not feasible, due to Josephson vortices penetration into the superconducting electrodes which drove the necessary field above the depairing field.

arXiv comment29 pages, 7+2 figures, Comments are welcome

References in corpus (21)

• The pseudogap in high-temperature superconductors: an experimental survey
• Long-range incommensurate charge fluctuations in (Y,Nd)Ba2Cu3O(6+x)
• The Nernst effect in high-$T_c$ superconductors
• The pseudogap: friend or foe of high Tc?
• Vanishing of phase coherence in underdoped Bi_2Sr_2CaCu_2O_8+d
• Three-Dimensional Charge Density Wave Order in YBa2Cu3O6.67 at High Magnetic Fields
• Resonant X-ray Scattering Study of Charge Density Wave Correlations in YBa${}_2$Cu${}_3$O${}_{6+x}$
• Diamagnetism and Cooper pairing above $T_c$ in cuprates
• On the superconductivity in the system with preformed pairs
• X-ray diffraction observation of charge density wave order at zero magnetic field in ortho-II YBa${}_2$Cu${}_3$O${}_{6.54}$
• Direct measurement of the upper critical field in a cuprate superconductor
• Momentum-dependent charge correlations in YBa${}_2$Cu${}_3$O${}_{6+\delta }$ superconductors probed by resonant x-ray scattering: Evidence for three competing phases
• Bounding the pseudogap with a line of phase transitions in YBCO cuprate superconductors
• Magnetic field controlled charge density wave coupling in underdoped YBa${}_2$Cu${}_3$O${}_{6+x}$
• Evidence of precursor superconductivity as high as 180 K from infrared spectroscopy
• Absolute values of the London penetration depth in YBa2Cu3O6+y measured by zero field ESR spectroscopy on Gd doped single crystals
• Parametric control of a superconducting flux qubit
• Diamagnetism of YBa${}_2$Cu${}_3$O${}_{6+x}$ crystals above $T_c$~: evidence for Gaussian fluctuations
• Josephson vortex lattice in layered superconductors
• Flux-flow resistivity anisotropy in the instability regime in the a-b plane of epitaxial YBCO thin films
• Pairing and the phase diagram of the normal coherence length ${\xi }_N(T,x)$ above $T_c$ of $L{a}_{2-x}S{r}_{x}Cu{O}_4$ thin films probed by the Josephson effect

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• Pair density wave, charge density wave and vortex in high Tc cuprates
• Detection of collective modes in unconventional superconductors using tunneling spectroscopy
• Proposal to measure the pair field correlator of a fluctuating pair density wave
• The Transformation of the Superconducting Gap to an Insulating Pseudogap at a Critical Hole Density in the Cuprates
• Linear dichroism infrared resonance in over-, under-, and optimally-doped cuprate superconductors
• Proximity effects and pair currents in cuprate junctions
• Observation of Josephson-like tunneling junction characteristics and positive magnetoresistance in Oxygen deficient Nickelate films of $N{d}_{0.8}S{r}_{0.2}Ni{O}_{3-\delta }$
• Precursory Cooper Flow in Ultralow-Temperature Superconductors