A quantitative vortex-fluid description of Nernst effect in Bi-based cuprate high-temperature superconductors

Abstract

We present a completely analytical vortex-fluid model describing several vortex-fluid phases of holedoped cuprate superconductors below and above T c . A key feature of the model is to synthesize several vortex damping mechanisms of scattering inside vortex core, core-core collisions and pinning. Accurate predictions for both magnetoresistance and Nernst effect are obtained, validated by measurements in six Bi-based cuprate samples over a wide range of temperature and magnetic fields, which strongly support the phase-fluctuation scenario in Bi-based cuprates. The model quantifies the unconventional vortex properties by a set of physical parameters, which adds quantitative contents to the discussions of pseudogap. A speculation is offered to use the vortex-fluid model as a first step towards achieving a comprehensive understanding of Nernst effect for all HTSC.xy GF must be smaller in most hole-doped cuprates due to OPEN ACCESS RECEIVED

Energy-length scaling of critical phase fluctuations in the cuprate pseudogap phase

“…Furthermore, above the T c dome, the BKT phase transition generates free thermal vortices in the low-T part (T c < T ≪ T*) of the pseudogap phase. The best circumstantial evidence for this scenario comes from diamagnetism and Nernst signals [95,104], which were accurately described by the time-dependent Ginzburg-Landau equation [105,106] and vortex transport theory [107]. These evidences confirm that a spatial organization of superconducting phase-fluctuations (i.e., the unbinding of vortex-antivortex pair) determines the cuprate superconducting transition.…”