I-V characteristics in multi-gap intrinsic Josephson junction stacks

We develop a theory for the AC Josephson effect in 2-gap intrinsic Josephson junction stacks. The coupled dynamical equations which the phase differences obey are derived from the phenomenological effective Lagrangian. The equations can describe the longitudinal Josephson plasma and the Leggett mode propagating in the c-direction. Numerical results for the I-V characteristics are presented. The switching current to the voltage state is greatly reduced. The multiple-branch structure appears in the I-V characteristics (74 words) (C) 2010 Elsevier B.V. All rights reserved.