Reduction of Dissipative Nonlinear Conductivity of Superconductors by Static and Microwave Magnetic Fields

A. Gurevich

doi:10.1103/PhysRevLett.113.087001

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Reduction of Dissipative Nonlinear Conductivity of Superconductors by Static and Microwave Magnetic Fields

A. Gurevich

DOI 10.1103/PhysRevLett.113.087001 · Physical Review Letters

T1

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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.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Nb Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	9.2	Pressure not reported	unknown