Quasiparticle current and phase locking of intrinsic Josephson junctions

On the base of our experiments on thin film Josephson junctions in mesa geo metry we discuss the quasiparticle branches of the intrinsic arrays within a tunnelling model using d-wave superconductor density of states. We find t emperature dependent current contributions and a zero bias anomaly. The coh erent behaviour is studied for intrinsic arrays with an additional side-wal l shunt. The existence of thresholds of phase locking at small as well as a t large inductances is demonstrated. We discuss the problems with experimen tal realisation of the shunts as well as with an alternative concept to enh ance phase locking in such arrays towards application as oscillators in the frequency range up to some THz. (C) 2001 Elsevier Science B.V. All rights reserved.