無外加磁場時Josephson穿遜接面間之自我共振模理論

Abstract

The effect of self-resonant modes without any external magnetic field in Josephson junction, the so-called "Anomalous DC Current Singularaities" by Chen et al. in 1971, is first quantitatively investigated by solving the Josephson's equation under the assumption of no external magnetic field but with a dc bias and open-ended cavity boundary conditions. The theory is on the basis of the nonlinear mutual interaction of harmonics of the superconducting current with the electrical and magnetic fields induced by the superconducting current itself in the junction cavity.A series of even-modes of current singularities in the dc current-voltage characteristics appears accordingly.It also allows us to explain the Q-value (quality value in the resonance cavity)dependence of the current singularities, behaviour of the cut-off voltage, and the maximum height of the first even-mode of the current singularities in the experimental observations.