Microshort-to-tunneling transition in Au-YBa2Cu3O7−δ single-crystal point contacts

Srikanth, H. ; Raychaudhuri, A. K. (1992) Microshort-to-tunneling transition in Au-YBa2Cu3O7−δ single-crystal point contacts Physical Review B: Condensed Matter and Materials Physics, 45 (1). pp. 383-388. ISSN 0163-1829

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Official URL: http://prb.aps.org/abstract/PRB/v45/i1/p383_1

Related URL: http://dx.doi.org/10.1103/PhysRevB.45.383


We report on the evolution of dynamic conductance curves [(dI/dV)-V] as a function of junction resistance in Au-YBa2Cu3O7−δ single-crystal point-contact junctions. We have demonstrated that it is possible to evolve continuously from a microshort (N-S) to a tunnel junction (N-I-S) by adjusting the contact pressure in the point-contact junction. At the lowest junction resistances, we see a peak in dI/dV at zero bias, which we explain as due to Andreev reflection. As the junction resistance is gradually increased, the zero-bias peak diminishes and gaplike features appear in the (dI/dV)-V curves. At even higher resistance, the zero-bias peak vanishes, all features get smeared out, and a linear dI/dV variation with the bias voltage is seen. Based on the similarity of (dI/dV)-V curves obtained in high-resistance Au-YBa2Cu3O7−δ junctions with those obtained in a nonsuperconducting perovskite oxide metal (Au-NaxWO3 junctions, x≃0.45), we suggest that the linear (dI/dV)-V curves arise due to inelastic scattering of electrons at a "metallic" layer on the surface of the superconductor.

Item Type:Article
Source:Copyright of this article belongs to The American Physical Society.
ID Code:42700
Deposited On:06 Jun 2011 07:18
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