6 research outputs found
Theory of Coherent -Axis Josephson Tunneling between Layered Superconductors
We calculate exactly the Josephson current for -axis coherent tunneling
between two layered superconductors, each with internal coherent tight-binding
intra- and interlayer quasiparticle dispersions. Our results also apply when
one or both of the superconductors is a bulk material, and include the usually
neglected effects of surface states. For weak tunneling, our results reduce to
our previous results derived using the tunneling Hamiltonian. Our results are
also correct for strong tunneling. However, the -axis tunneling results of
Tanaka and Kashiwaya are shown to be incorrect in any limit. In addition, we
consider the -axis coherent critical current between two identical layered
superconductors twisted an angle about the -axis with respect to
each other. Regardless of the order parameter symmetry, our coherent tunneling
results using a tight-binding intralayer quasiparticle dispersion are
inconsistent with the recent -axis twist bicrystal
BiSrCaCuO twist junction experiments of Li {\it et
al.}Comment: 11 pages, 13 figures, submitted to Physical Review