15 research outputs found
Conductance of non-ballistic point contacts in hybrid systems "normal metal/superconductor" Cu/Mo-C and Cu/LaOFFeAs
We consider the shape of the curves of "Andreev" conductance of non-ballistic
point contact NS heterosystems depending on the bias voltage at the contact.
The obtained shape of those curves is caused by the contribution from the
mechanism of coherent scattering by impurities which doubles the scattering
cross section. The behavior of generalized and differential conductance is
compared for ballistic and non-ballistic transport regimes. The criteria are
considered allowing one to discriminate between those regimes with the
corresponding conduction curves similar in appearance. The analysis is extended
to the case of non-ballistic transport in NS point contacts with exotic
superconductors, molybdenum carbide Mo-C and oxypnictide
La[OF]FeAs from a group of iron-based superconductors
Nonequilibrium Josephson effect in short-arm diffusive SNS interferometers
We study non-equilibrium Josephson effect and phase-dependent conductance in
three-terminal diffusive interferometers with short arms. We consider strong
proximity effect and investigate an interplay of dissipative and Josephson
currents co-existing within the same proximity region. In junctions with
transparent interfaces, the suppression of the Josephson current appears at
rather large voltage, , and the current vanishes at
. Josephson current inversion becomes possible in junctions with
resistive interfaces, where the inversion occurs within a finite interval of
the applied voltage. Due to the presence of considerably large and
phase-dependent injection current, the critical current measured in a current
biased junction does not coincide with the maximum Josephson current, and
remains finite when the true Josephson current is suppressed. The voltage
dependence of the conductance shows two pronounced peaks, at the bulk gap
energy, and at the proximity gap energy; the phase oscillation of the
conductance exhibits qualitatively different form at small voltage ,
and at large voltage .Comment: 11 pages, 9 figures, revised version, to be published in Phys. Rev.