Static Charge Coupling of Intrinsic Josephson Junctions

Since the discovery of the intrinsic Josephson effect not only the typical properties of conventional junctions were demonstrated [1], but also unique and surprising features like the coupling of Josephson oscillations to phonons [2] have been discovered. There has also been a considerable interest in the influence of nonequilibrium effects on the I − V -characteristic and collective modes [3– 9], as the quasi two-dimensional superconducting layers are expected to be more sensitive to external perturbations than bulk materials. Recent measurements of Shapirosteps on the resistive branch [10,11] suggest to study the role of nonequilibrium effects on these, as the in depth theoretical understanding of this problem is important for any high-precision applications of high temperature superconductors (HTSC) as a voltage standard. This paper is organized as follows: The microscopic theory for the electronic transport between the superconducting layers is developed and the close analogy of the static case to the normal state is pointed out. Then the consequences for the IV -curve, the dispersion of collective modes and the position of Shapiro steps are being discussed. Further technical details can be found in [7,8] and in a forthcoming publication [12].