Reduction of Dissipative Nonlinear Conductivity of Superconductors by Static and Microwave Magnetic Fields
Abstract
A theory of dissipative nonlinear conductivity, σ1(ω,H), of s-wave superconductors under strong electromagnetic fields at low temperatures is proposed. Closed-form expressions for σ1(H) and the surface resistance Rs(ω ,H) are obtained in the nonequilibrium dirty limit for which σ1(H) has a significant minimum as a function of a low-frequency (ℏω ≪kBT) magnetic field H. The calculated microwave suppression of Rs(H) is in good agreement with recent experiments on alloyed Nb resonator cavities. It is shown that superimposed dc and ac fields, H =H0+Hacosωt, can be used to reduce ac dissipation in thin film nanostructures by tuning σ1(H0) with the dc field.
- Publication:
-
Physical Review Letters
- Pub Date:
- August 2014
- DOI:
- arXiv:
- arXiv:1408.4476
- Bibcode:
- 2014PhRvL.113h7001G
- Keywords:
-
- 74.25.nn;
- 74.25.Ha;
- 74.40.Gh;
- 74.78.Na;
- Magnetic properties;
- Mesoscopic and nanoscale systems;
- Condensed Matter - Superconductivity
- E-Print:
- PRL, 113, 087001 (2014)