Free flux flow resistivity in strongly overdoped high-T_c cuprate; purely viscous motion of the vortices in semiclassical d-wave superconductor

TL;DR

This study investigates the flux flow resistivity in overdoped d-wave cuprate superconductors, revealing unique magnetic field dependencies that differ from conventional s-wave superconductors, and discusses underlying dissipation mechanisms.

Contribution

It provides the first detailed measurements of free flux flow resistivity in strongly overdoped d-wave cuprates, highlighting distinct field-dependent behaviors and proposing mechanisms involving quasiparticle dynamics.

Findings

FFF resistivity increases linearly at low fields, much larger than in s-wave superconductors.

At higher fields, FFF resistivity scales with the square root of the magnetic field.

Results suggest altered quasiparticle relaxation and participation in energy dissipation in d-wave superconductors.

Abstract

We report the free flux flow (FFF) resistivity associated with a purely viscous motion of the vortices in moderately clean d-wave superconductor Bi:2201 in the strongly overdoped regime (T_c=16K) for a wide range of the magnetic field in the vortex state. The FFF resistivity is obtained by measuring the microwave surface impedance at different microwave frequencies. It is found that the FFF resistivity is remarkably different from that of conventional s-wave superconductors. At low fields (H<0.2H_c2) the FFF resistivity increases linearly with H with a coefficient which is far larger than that found in conventional s-wave superconductors. At higher fields, the FFF resistivity increases in proportion to \sqrt H up to H_c2. Based on these results, the energy dissipation mechanism associated with the viscous vortex motion in "semiclassical" d-wave superconductors with gap nodes is discussed. Two possible scenarios are put forth for these field dependence; the enhancement of the quasiparticle relaxation rate and the reduction of the number of the quasiparticles participating the energy dissipation in d-wave vortex state.