Dynamical Breaking of Charge Neutrality in Intrinsic Josephson Junctions: Common Origin for Microwave Resonant Absorptions and Multiple-Branch Structures in theI−VCharacteristics

We demonstrate that both microwave resonant absorptions and multiple-branch structures in the I-V characteristics observed in intrinsic Josephson junctions are caused by the dynamical breaking of the charge neutrality inside the atomic-scale superconducting layers. The Lagrangian for the time-dependent Lawrence-Doniach model incorporating the charge neutrality breaking effect is proposed. On the basis of the Lagrangian, the longitudinal collective Josephson plasma mode is proved to exist. The branching behaviors in the I-V curves are almost completely reproduced by careful numerical simulations for the model equation derived from the Lagrangian.