Equilibrium properties of a Josephson-junction ladder with screening effects
- Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales de Aragon, Consejo Superior de Investigaciones Cientificas, Universidad de Zaragoza, 50009 Zaragoza (Spain)
- Dipartimento di Fisica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma (Italy)
We calculate the ground-state phase diagram of a Josephson-junction ladder when screening field effects are taken into account. We study the ground-state configuration as a function of the external field, the penetration depth, and the anisotropy of the ladder, using different approximations to the calculation of the induced fields. A series of tongues, characterized by the vortex density {omega}, is obtained. The vortex density of the ground state, as a function of the external field, is a devil{close_quote}s staircase, with a plateau for every rational value of {omega}. The width of each of these steps depends strongly on the approximation made when calculating the inductance effect: If the self-inductance matrix is considered, the {omega}=0 phase tends to occupy all the diagram as the penetration depth decreases. If, instead, the whole inductance matrix is considered, the width of any step tends to a nonzero value in the limit of very low penetration depth. We have also analyzed the stability of some simple metastable phases: Screening fields are shown to enlarge their stability range. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 399822
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 54, Issue 22; Other Information: PBD: Dec 1996
- Country of Publication:
- United States
- Language:
- English
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