Dynamic pair-breaking current, critical superfluid velocity and nonlinear electromagnetic response of nonequilibrium superconductors

Abstract

We report numerical calculations of a dynamic pairbreaking current density $J_d$ and a critical superfluid velocity $v_d$ in a nonequilibrium superconductor carrying a uniform, large-amplitude ac current density $J(t)=J_a\sin \Omega t$ with $\Omega$ well below the gap frequency $\Omega \ll {\Delta }_0/\hslash$. The dependencies $J_d(\Omega ,T)$ and $v_d(\Omega ,T)$ near the critical temperature $T_c$ were calculated from either the full time-dependent nonequilibrium equations for a dirty s-wave superconductor and the time-dependent Ginzburg-Landau (TDGL) equations for a gapped superconductor, taking into account the GL relaxation time of the order parameter ${\tau }_{GL}$ and the inelastic electron-phonon relaxation time of quasiparticles ${\tau }_E$. We show that both approaches give similar frequency dependencies of $J_d(\Omega )$ and $v_d(\Omega )$ which gradually increase from their static pairbreaking GL values $J_c$ and $v_c$ at $\Omega {\tau }_E\ll 1$ to $\sqrt{2}{J}_c$ and $\sqrt{2}{v}_c$ at $\Omega {\tau }_E\gg 1$. 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 $H=H_a\sin \Omega t$ 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 ${\tau }_E$ increases.

References in corpus (25)

• Superconductivity in one dimension
• Nonlinear Meissner Effect in CuO Superconductors
• Tunable superconducting nanoinductors
• The Nonlinear Meissner Effect in Unconventional Superconductors
• Density of states in a superconductor carrying a supercurrent
• Probing individual topological tunnelling events of a quantum field via their macroscopic consequences
• Superheating field of superconductors within Ginzburg-Landau theory
• Reduction of Dissipative Nonlinear Conductivity of Superconductors by Static and Microwave Magnetic Fields
• Field-dependent nonlinear surface resistance and its optimization by surface nano-structuring in superconductors
• Temperature dependence of the superheating field for superconductors in the high-k London limit
• Nonlinear Current Response of a d-wave Superfluid
• Effect of Impurities on the Superheating field of Type II superconductors
• Different single photon response of wide and narrow superconducting MoSi strips
• Quasiparticle scattering time in superconducting films: from dirty to clean limit
• Diamagnetic Response of Normal-metal -- Superconductor Double Layers
• Is the nonlinear Meissner effect unobservable?
• Current-Induced Pair Breaking in Magnesium Diboride
• Diamagnetic Response of an N-S-Proximity System at Arbitrary Impurity Concentration
• Magnetic breakdown in a normal-metal - superconductor proximity sandwich
• The Effect of Inhomogeneous Surface Disorder on the Superheating Field of Superconducting RF Cavities
• Measurement of the nonlinear Meissner effect in superconducting Nb films using a resonant microwave cavity: A probe of unconventional pairing symmetries
• Response of thin-film SQUIDs to applied fields and vortex fields: Linear SQUIDs
• Non-bolometric bottleneck in electron-phonon relaxation in ultra-thin WSi film
• Free Energy and Magnetic Penetration Depth of a $d$-Wave Superconductor in the Meissner State
• Proximity-induced screening and its magnetic breakdown in mesoscopic hybrid structures

Cited by in corpus (4)

• Tuning microwave losses in superconducting resonators
• Effect of random pinning on nonlinear dynamics and dissipation of a vortex driven by a strong microwave current
• Impact of border defects on the magnetic flux penetration in superconducting films
• Fast Dynamics of Vortices in Superconductors