Macroscopic Quantum Tunneling in d -Wave YBa2Cu3O7−δ Josephson Junctions
Thilo Bauch, Floriana Lombardi, Francesco Tafuri +4 more
The escape rate from the zero voltage state in a superconducting Josephson junction (JJ) is determined by the temperature, but it saturates at low temperature due to macroscopic quantum tunneling (MQT). Complications due to d-wave symmetry in a high temperature superconductor, like low energy quasiparticles and an unconventional current-phase relation, may influence the escape rate. We report, for the first time to our knowledge, the observation of MQT in a YBa(2)Cu(3)O(7-delta) grain boundary biepitaxial JJ. This proves that dissipation can be significantly reduced by a proper junction configuration, which is of significance for quantum coherence.
Physical Review Letters•Mar 3, 2005•158 citations