1. Multiple Andreev Reflections and Enhanced Shot Noise in Diffusive Superconducting-Normal-Superconductor Junctions
- Author
-
Göran Wendin, E. N. Bratus, E. V. Bezuglyi, and Vitaly Shumeiko
- Subjects
Superconductivity ,Physics ,Mesoscopic physics ,Condensed matter physics ,Condensed Matter::Superconductivity ,Star (game theory) ,Shot noise ,General Physics and Astronomy ,Charge (physics) ,Inelastic scattering ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Noise (electronics) ,Andreev reflection - Abstract
We study the dc conductance and current fluctuations in mesoscopic diffusive SNS junctions at subgap applied voltages $\mathrm{eV}l2\ensuremath{\Delta}$. We find that in spite of the multiple Andreev reflections, the current-voltage characteristic of a long SNINS structure obeys Ohm's law. At the same time, non-equilibrium heating of subgap electrons produces giant shot noise with pronounced subharmonic gap structure which corresponds to stepwise growth of the effective transferred charge. At $\mathrm{eV}\ensuremath{\rightarrow}0$, the shot noise approaches the magnitude of the Johnson-Nyquist noise with the effective temperature ${T}^{\ensuremath{\star}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{\Delta}/3$. We analyze the role of inelastic scattering and present a criterion of strong nonequilibrium.
- Published
- 1999