We calculate suppression of inter- and intra-layer superconducting currents due to equilibrium phase fluctuations and find that, in contrast to a recent prediction, the effect of thermal fluctuations cannot account for linear temperature dependence of the superfluid density in high-Tc superconductors at low temperatures. Quantum fluctuations are found to dominate over thermal fluctuations at low temperatures due to hardening of their spectrum caused by the Josephson plasma resonance. Near Tc sizeable thermal fluctuations are found to suppress the critical current in the stack direction stronger than in the direction along the layers. Fluctuations of quasi-particle branch imbalance make the spectral density of voltage fluctuations at small frequencies non-zero, in contrast to what may be expected from a naive interpretation of Nyquist formula.
- Layered crystal
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering