Interlayer tunneling of quasiparticles and Cooper pairs in Bi-2212 from experiments on small stacks

Abstract

The interlayer tunneling has been studied on high quality Bi-2212 stacks of micron to the submicron lateral size. We found that low temperature and low voltage tunneling I– V characteristics can be self-consistently described by Fermi-liquid model for a d-wave superconductor with a significant contribution from coherent interlayer tunneling. For micron-sized stacks we found very clear Fraunhofer type dependence of critical current across the stack on parallel magnetic field with periodicity corresponding to one flux quantum per elementary junction. The gap and pseudogap interplay with variation of temperature and magnetic field has been extracted from the I– V characteristics. We consider also the role of charging effects for submicron stacks.