Springer LINK: The European Physical Journal B - Abstract Volume 5 Issue 3 (1998) pp 465-471

The European Physical Journal B

ISSN: 1434-6028 (printed version)
ISSN: 1434-6036 (electronic version)

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Abstract Volume 5 Issue 3 (1998) pp 465-471

A microscopic model for the intrinsic Josephson tunneling in high-$\mathsf{T_C}$ superconductors

W. Hanke (1), O. Schmitt (1), H. Endres (1), R. Kleiner (2), P. Müller (2)

(1) Institut für Theoretische Physik, Universität Würzburg, 97074 Würzburg, Germany
(2) Physikalisches Institut III, Universität Erlangen-Nürnberg, 91058 Erlangen, Germany

Received: 24 February 1998 / Revised: 28 April 1998 / Accepted: 23 June 1998

Abstract: A quantitative analysis of a microscopic model for the intrinsic Josephson effect in high-temperature superconductors based on interlayer tunneling is presented both within a mean-field BCS evaluation and a numerically essentially exact Quantum Monte-Carlo study. The pairing correlations in the CuO₂-planes are modelled by a 2D Hubbard model with attractive interaction, a model which accounts well for some of the observed features such as the short planar coherence length. The stack of Hubbard planes is arranged on a torus, which is threaded by a magnetic flux. The current perpendicular to the planes is calculated as a function of applied flux (i.e. the phase), and - after careful elimination of finite-size effects due to single-particle tunneling - found to display a sinusoidal field dependence in accordance with interlayer Josephson tunneling. Studies of the temperature dependence of the supercurrent reveal at best a mild elevation of the Josephson transition temperature compared to the planar Kosterlitz-Thouless temperature. These and other results on the dependence of the model parameters are compared with a standard BCS evaluation.

PACS. 74.20.-z Theories and models of superconducting state - 74.20.Mn Nonconventional mechanisms (spin fluctuations, polarons and bipolarons, resonating valence bond model, anyon mechanism, marginal Fermi liquid, Luttinger liquid, etc.) - 71.10.Fd Lattice fermion models (Hubbard model, etc.)

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