OBSERVATION OF D-WAVE INTERFERENCE PATTERN - SHORT JUNCTION IS CRUCIAL

The properties of a one-dimensional O-pi-Josephson junction; consiting of an s-d junction or selected boundaries between three suitably orie nted d-wave superconductors, are studied. It is shown that a d-wave ty pe interference pattern can only be observed in the field-modulated cr itical current if the junction is short compared to the Josephson pene tration depth. However, the behavior of a O-pi junction is found to be indistinguishable from that of a O-junction between s-wave supercondu ctors ill the long junction limit, due to the formation of a pi-vortex .