Modeling Voltage Rectification Effects on Mesoscopic Superconducting Devices

M.F. CARUSELA; V. P. RAMUNNI; V. I. MARCONI

Buenos Aires

Workshop; At the Frontiers of Condensed Matter V, Current Trends and Novel Materials; 2010

Titulo: Modeling Voltage Rectification Effects on Mesoscopic Superconducting Devices AUTORES: Carusela, M.F.,1 Ramunni, V.P.,2 and Marconi, V.I.3 AFILIACIONES 1 Instituto de Ciencias, UNGS, J.M. Guti´errez 1150, 1613 Los Polvorines, Argentina - CONICET. 2 Departamento de Materiales, CAC-CNEA, Avda. General Paz 1499, 1650 San Mart´ın, Argentina - CONICET. 3 Grupo de Teorıa de la Materia Condensada, FaMAF, Universidad Nacional de Cordoba, 5000 Cordoba, Argentina - IFEG-CONICET. RESUMEN The general and central idea that motivates this work is the recent technological progress allowing the observation of ratchet effects in very complex systems such as cold atoms, electrons in semiconductors, vor- tices in superconductors just to mention a few. But the main question on this field is that “is not simple” in each case to know feasibly which are the mecha- nisms underlying these many bodies complex effects in condensed matter. In particular, motivated for recent experiments reporting voltage rectification ef- fects in mesoscopic superconducting triangles [Schil- dermans et al, PRB 76, 224501, 2007] we simulated an improved model for such a system. We studied thermal fluctuations effects and capacitive effects on a Small Josephson Junction Closed Loop that mimics the rectification phenomena observed experimentally due to the superposition of a field induced persistent current with the bias current. At finite temperature we predicted that the amplitude of the rectified sig- nal depends strongly on the current contacts config- uration on the Josephson Junction Ring (weak link type junctions), in coincidence with the observations on the mesoscopic superconducting triangle sample. In addition we analize the range of parameters where a closed loop of capacitive junctions is an appropriate model to explain the experimental observation. In short, in this work we conclude that the closed loop of SNS Josephson Junctions is a good and robust enough model in a considerable range of thermal fluctuations to explain the observed voltage rectification effects on mesoscopic superconducting samples.