DYNAMICS OF A SINGLE TRIANGULAR PLAQUETTE OF JOSEPHSON-JUNCTION ARRAYS

The single triangular plaquette array of Josephson junctions under the transverse magnetic field with varying current configurations has been studied as the simplest model which may emulate some of the basic features of the large Josephson junction arrays. For symmetric current configuration, integer and fractional steps are observed in the I-V curve for non-zero magnetic field. However, when the symmetry in the dc currents is broken, we have observed chaotic voltage oscillations and the non-monotonic I-V curve and explained the mechanism for chaos. We have found that for fixed magnetic field the symmetry in the voltage drops breaks down for some critical I-dc and obtained the phase diagram for the voltage symmetry breaking in the space of the dc current and the asymmetry parameter.