Rocking Ratchets in Two-Dimensional Josephson Networks: Collective Effects and Current Reversal.

VERONICA I. MARCONI

PHYSICAL REVIEW LETTERS

The American Physical Society

Año: 2007 vol. 98 p. 470061 - 470064

0031-9007

 A  detailed numerical study on the  directed motion of ac-driven  vortices and antivortices in  2DJosephson  junction arrays (JJA) with an asymmetric  periodic pinning potential is reported.  Dc-voltage rectification shows a strong dependence on vortex density as well as an inversion of the vortex flow direction with ac amplitude for a wide range of  vortex density around $f$=1/2 ($f$=$Ha^2 / Phi_0$), in good agreement with recent  experiments by Shal´om and Pastoriza [Phys. Rev. Lett. {f 94},  177001 (2005)]. The study of vortex structures, spatial and temporal correlations, and vortex-antivortex  pairs formation gives insight into a purely collective mechanism behind the current reversal effect.