Quantum effects in small-capacitance single Josephson junctions
2003 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 67, no 9Article in journal (Refereed) Published
We have measured the current-voltage (I-V) characteristics of small-capacitance single Josephson junctions at low temperatures (T = 0.02-0.6 K), where the strength of the coupling between the single junction and the electromagnetic environment was controlled with one-dimensional arrays of dc superconducting quantum interence devices (SQUIDs). The single-junction I-V curve is sensitive to the impedance of the environment, which can be tuned in situ. We have observed Coulomb blockade of Cooper-pair tunneling and even a region of negative differential resistance, where the zero-bias resistance R-0' of the SQUID arrays is much higher than the quantum resistance R-K = h/e(2)approximate to26 kOmega. The negative differential resistance is evidence of the coherent single-Cooper-pair tunneling within the theory of current-biased single Josephson junctions. Based on this theory, we have calculated the I-V curves numerically in order to compare then with the experimental ones at R-0'>>R-K. The numerical calculation agrees with the experiments qualitatively. We also discuss the R-0' dependence of the single-Josephson-junction I-V curve in terms of the superconductor-insulator transition driven by changing the coupling to the environment.
Place, publisher, year, edition, pages
2003. Vol. 67, no 9
superconductor-insulator transition, phase-transition, tunnel-junctions, coulomb-blockade, electromagnetic environment, dissipative dynamics, bloch oscillations, arrays, resistance, fabrication
IdentifiersURN: urn:nbn:se:kth:diva-22390DOI: 10.1103/PhysRevB.67.094505ISI: 000182019300108OAI: oai:DiVA.org:kth-22390DiVA: diva2:341088
QC 201005252010-08-102010-08-10Bibliographically approved