Dynamic Pair-Breaking Current, Critical Superfluid Velocity, and Nonlinear Electromagnetic Response of Nonequilibrium Superconductors

Authors

Ahmad Sheikhzada, Old Dominion UniversityFollow
Alex Gurevich, Old Dominion UniversityFollow

Document Type

Article

Publication Date

2020

DOI

10.1103/PhysRevB.102.104507

Publication Title

Physical Review B

Volume

102

Issue

10

Pages

104507 (15 pp.)

Abstract

We report numerical calculations of a dynamic pair-breaking current density J_d and a critical superfluid velocity v_d in a nonequilibrium superconductor carrying a uniform, large-amplitude AC current density J(t)=J_asinΩt with Ω well below the gap frequency Ω ≪ Δ₀/h. The dependencies J_d(Ω,T) and v_d(Ω,T) near the critical temperature T_cwere calculated from either the full time-dependent nonequilibrium equations for a dirty s-wave superconductor or the time-dependent Ginzburg-Landau (TDGL) equations for a gapped superconductor, taking into account the GL relaxation time of the order parameter GL and the inelastic electron-phonon relaxation time of quasiparticles _𝒯E. We show that both approaches give similar frequency dependencies of Jd(Ω) and vd(Ω) which gradually increase from their static pair-breaking GL values J_c and v_cat E1 to 2Jc and vc at Ω_𝒯E≪ 1 to √2J_{c and} √2v_c at Ω_𝒯E ≫ 1. Here J_d, v_d and a dynamic superheating field at which the Meissner state becomes unstable were calculated in two different regimes of a fixed AC current and a fixed AC superfluid velocity induced by the applied AC magnetic field H=H_asinΩt in a thin superconducting filament or a type-II superconductor with a large GL parameter. We also calculated a nonlinear electromagnetic response of a nonequilibrium superconducting state, particularly a dynamic kinetic inductance and a dissipative quasiparticle conductivity, taking into account the oscillatory dynamics of superconducting condensate and the kinetics of quasiparticles driven by a strong AC current. It is shown that an AC current density produces multiple harmonics of the electric field, the amplitudes of the higher-order harmonics diminishing as _𝒯E increases.

Comments

© 2020 American Physical Society.

Publisher's version is available at https://doi.org/10.1103/PhysRevB.102.104507.

Original Publication Citation

Sheikhzada, A., & Gurevich, A. (2020). Dynamic pair-breaking current, critical superfluid velocity, and nonlinear electromagnetic response of nonequilibrium superconductors. Physical Review B, 102(10), (15 pp.), Article 104507 https://doi.org/10.1103/PhysRevB.102.104507

ORCID

0000-0003-0759-8941 (Gurevich)

Repository Citation

Sheikhzada, Ahmad and Gurevich, Alex, "Dynamic Pair-Breaking Current, Critical Superfluid Velocity, and Nonlinear Electromagnetic Response of Nonequilibrium Superconductors" (2020). Physics Faculty Publications. 449.
https://digitalcommons.odu.edu/physics_fac_pubs/449