Title: Theoretical perspectives for Microwave Applications of
Intrinsic Josephson junctions


Presenting Author: 

Ch. Helm 

Los Alamos National Laboratory, Division T-11 Mail Stop B-262, 
Los Alamos NM 87501 USA

Coauthors:

Ch.Preis, J. Keller

Institut  fur Theoretische  Physik,  Universitat  Regensburg, 
D-93040 Regensburg,  Germany

S. Rother, P. Mueller, 
Physikalisches Institut, University of Erlangen, 

R. Kleiner
Physikalisches Institut - Experimentalphysik II, Universität Tuebingen
Morgenstelle 14, 
D-72076 Tuebingen
Germany



Abstract: 

The interaction of intrinsic Josephson oscillations with phonons and its 
manifestation as resonances in the current-voltage characteristics has 
been recently established. In this contribution the principle perspectives of 
this new phenomenon from the point of view of applications are being 
considered. 
In particular, the interaction of different resistive junctions via 
the excitation of phonons in c-direction can lead to phasecoherence and 
consequently to a higher output power if used as a microwave source. 
Also the mixing amplitude  is enhanced, if in the 
superconducting state one of the external frequencies coincides with an
internal phonon eigenfrequency or if the junction is biased at a phonon 
resonance in the resistive state. 
In addition to this, recent measurements of Shapirosteps on the resistive 
branches of the intrinsic Josephson effect showed a shift of the step from the 
expected position. Although the interpretation of this effect is still
controversial, theoretical perspectives are given for a possible violation of 
the Josephson relation due to the scalar electromagnetic potential.