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Counterintuitive Consequence of Heating in Strongly-Driven Intrinsic-Junctions of Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ Mesas
- Source :
- Phys. Rev. B 81, 224518 (2010)
- Publication Year :
- 2009
-
Abstract
- Anomalously high and sharp peaks in the conductance of intrinsic Josephson junctions in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ (Bi2212) mesas have been universally interpreted as superconducting energy gaps, but here we show they are a result of heating. This interpretation follows from a direct comparison to the equilibrium gap, $\mathit \Delta$, measured in break junctions on similar Bi2212 crystals. As the dissipated power increases with a greater number of junctions in the mesa, the conductance peak abruptly sharpens and its voltage decreases to well below 2$\mathit \Delta$. This sharpening, found in our experimental data, defies conventional intuition of heating effects on tunneling spectra, but it can be understood as an instability into a nonequilibrium two-phase coexistent state. The measured peak positions occur accurately within the voltage range that an S-shaped backbending is found in the {\it calculated} current-voltage curves for spatially {\it uniform} self-heating and that S-shape implies the potential for the uniform state to be unstable.<br />Comment: 10 pages, 7 figures
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. B 81, 224518 (2010)
- Publication Type :
- Report
- Accession number :
- edsarx.0911.1420
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevB.81.224518