Tunable supercurrent in superconductor/normal metal/superconductor Josephson junctions |
| |
| Institution: | 1. Université de Nice Sophia-Antipolis, INLN, CNRS, 06560 Valbonne, France;2. Institut-Lorentz, Universiteit Leiden, P.O. Box 9506, 2300 RA Leiden, The Netherlands;3. Aix Marseille Université, CNRS, CPT, UMR 7332, 13288 Marseille, France;4. Université de Toulon, CNRS, CPT, UMR 7332, 83957 La Garde, France;1. IDTQ – Grupo Vinculado PLAPIQUI – CONICET, Córdoba, Argentina;2. UNC, Facultad de Ciencias Exactas Físicas y Naturales, Av. Vélez Sarsfield 1611, CU, Córdoba, Argentina;3. Farmacognosia, Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba – IMBIV, CONICET, Ciudad Universitaria, Córdoba, Argentina;4. PLAPIQUI (UNS-CONICET), Cno. La Carrindanga Km 7, Bahía Blanca, Argentina;5. UTN, Facultad Regional San Francisco, Av de la Universidad 501, San Francisco, Córdoba, Argentina;1. Department of Electrical and Computer Engineering, University of Illinois at Chicago, 851 South Morgan Street, M/C 154, Chicago, IL 60607, USA;2. Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street (SEO 218), Chicago, IL 60607, USA;3. Department of Physics, University of Illinois at Chicago, 845 W. Taylor St. (M/C 273), Chicago, IL 60607, USA |
| |
| Abstract: | When two superconductors are connected by a weak link a supercurrent flows determined by the difference in the macroscopic quantum phases of the superconductors. Originally, this phenomenon was discovered by Josephson for the case of a weak link formed by a thin tunnel barrier. The supercurrent I is related to the phase difference ϕ through the Josephson current–phase relation, I = Icsin ϕ, with Ic, the critical current, depending on the properties of the weak link. A similar relation holds for weak links consisting of a normal metal, a semiconductor or a constriction . In all cases, the phase differenceϕ = 0 when no supercurrent flows through the junction, and ϕ increases monotonically with increasing supercurrent until the critical current is reached. Using nanolithography techniques we have succeeded in making and studying a Josephson junction with a normal metal weak link, in which we have direct access to the microscopic current-carrying states inside the link. We find that the fundamental Josephson relation can be changed fromI = Icsin ϕ toI = Icsin(ϕ + π), i.e. to a π -junction, by suitably controlling the energy distribution of the current-carrying states in the normal metal. This fundamental change in the way these Josephson junctions behave has potential implications for their use in superconducting electronics as well as (quantum) logic circuits based on superconductors. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
