Phonons in intrinsic Josephson systems with parallel magnetic field
  Subgap resonances in the I-V curves of layered superconductors are explained by the coupling between Josephson oscillations and phonons with dispersion in c-direction. In the presence of a magnetic field applied parallel to the layers additional structures due to fluxon motion appear. Their coupling with phonons is investigated theoretically and a shift of the phonon resonances in strong magnetic fields is predicted. 
C. Preis, C. Helm, K. Schmalzl, J. Keller, R. Kleiner, P. Mueller