Influence of vortices and phase fluctuations on thermoelectric transport properties of superconductors in a magnetic field

Abstract

We study heat transport and thermoelectric effects in two-dimensional superconductors in a magnetic field. These are modeled as granular Josephson-junction arrays, forming either regular or random lattices. We employ two different models for the dynamics, relaxational model-A dynamics or resistively and capacitively shunted Josephson junction (RCSJ) dynamics. We derive expressions for the heat current in these models, which are then used in numerical simulations to calculate the heat conductivity and the Nernst coefficient for different temperatures and magnetic fields. At low temperatures and zero magnetic field the heat conductivity in the RCSJ model is calculated analytically from a spin wave approximation, and is seen to have an anomalous logarithmic dependence on the system size, and also to diverge in the completely overdamped limit C -> 0. From our simulations we find at low magnetic fields that the Nernst signal displays a characteristic "tilted hill" profile similar to experiments and a non-monotonic temperature dependence of the heat conductivity. We also investigate the effects of granularity and randomness, which become important for higher magnetic fields. In this regime geometric frustration strongly influences the results in both regular and random systems and leads to highly non-trivial magnetic field dependencies of the studied transport coefficients.

References in corpus (25)

• Thermal conduction in classical low-dimensional lattices
• Heat Transport in low-dimensional systems
• Theory of the Nernst effect near quantum phase transitions in condensed matter, and in dyonic black holes
• The Nernst effect in high-$T_c$ superconductors
• Granular Electronic Systems
• Thermoelectric Response of an Interacting Two-Dimensional Electron Gas in Quantizing Magnetic Field
• Gaussian superconducting fluctuations, thermal transport, and the Nernst effect
• Fourier's Law for a Harmonic Crystal with Self-consistent Stochastic Reservoirs
• Observation of the Nernst signal generated by fluctuating Cooper pairs
• Giant Nernst Effect due to Fluctuating Cooper Pairs in Superconductors
• Nernst effect and diamagnetism in phase fluctuating superconductors
• Nernst effect, quasiparticles, and d-density waves in cuprates
• Fluctuations of the superconducting order parameter as an origin of the Nernst effect
• Vortex dynamics for two-dimensional XY models
• Nernst effect in the vortex-liquid regime of a type-II superconductor
• A length scale for the superconducting Nernst signal above T${}_c$ in Nb${}_{0.15}$Si${}_{0.85}$
• Quasiparticle Nernst effect in stripe-ordered cuprates
• Melting and transverse depinning of driven vortex lattices in the periodic pinning of Josephson junction arrays
• Nernst effect as a probe of superconducting fluctuations in disordered thin films
• Nernst effect of the new iron-based superconductor LaO${}_{1-x}$F${}_x$FeAs
• Quantum kinetic approach to the calculation of the Nernst effect
• Magnetothermoelectric Response near Quantum Critical Points
• Quasiparticle Nernst effect in the cuprate superconductors from the d-density wave theory of the pseudogap phase
• Superconducting transition of a two-dimensional Josephson junction array in weak magnetic fields
• Anomalous Nernst effect and heat transport by vortex vacancies in granular superconductors

Cited by in corpus (3)

• Scaling, Finite Size Effects, and Crossovers of the Resistivity and Current-Voltage Characteristics in Two-Dimensional Superconductors
• Nernst Sign-Reversal in the Hexatic Vortex Phase of Weakly Disordered a-MoGe Thin Films
• Phase-dependent heat current of granular Josephson junction for different geometries