Current-carrying states in superconductor/insulator and superconductor/semiconductor superlattices in the mesoscopic regime
✍ Scribed by S.V. Kuplevakhsky; A.V. Naduev; S.V. Naydenov
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 135 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0749-6036
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✦ Synopsis
We discuss some of the basic theoretical aspects of current-carrying states in superconducting superlattices with tunnel barriers in the mesoscopic regime, when p -1 0 a ξ 0 (a is the superconducting layer thickness, p 0 is the Fermi momentum, ξ 0 is the BCS coherence length and = 1). We establish the necessary conditions for the observation of the classical Josephson effect (with sinusoidal current-phase dependence) and derive self-consistent analytical expressions for the critical Josephson current. These expressions are proportional to the small factor a/ξ 0 and have unusual temperature dependence as compared with the single-junction case. For certain parameter values, the superconducting gap exhibits an exponential decrease due to pair-breaking effect of the supercurrent. The supercurrent can completely destroy the superconductivity of the system above a certain characteristic temperature T * . In this paper, we also study the effect of intrabarrier exchange interactions. We show that this effect is strongly enhanced compared with the single-junction case and can manifest itself in an exponential decrease of the critical temperature.