d-wave YBCO Josephson junctions in the quantum phase and charge limit
Thilo Bauch
Chalmers University of Technology, Göteborg
Tuesday, 10 February 2009, 15:15
Seminar room F
Abstract:
We present direct observation of macroscopic quantum properties in an all high
critical temperature superconductor (HTS) d-wave Josephson junction. Although
dissipation caused by low energy excitations is expected to strongly suppress
quantum effects we demonstrate macroscopic quantum tunneling [1] and energy level
quantization [2] in our d-wave Josephson junction.
The results clearly indicate that the role of dissipation mechanisms in high
temperature superconductors has to be revised, and may also have consequences for
a new class of solid state "quiet" quantum bit with superior coherence time.
Moreover we realized for the first time an all-HTS single electron tunneling
transistor. This device is a powerful tool to probe the quasiparticle spectrum in
HTS materials and should give valuable information about dissipation processes in
HTS based quantum circuits.
[1] T. Bauch et al., Phys. Rev. Lett. 94, 087003 (2005).
[2] T. Bauch et al, Science 311, 57 (2006).