Interplay between Vortex Dynamics and Superconducting Gap Structure in Layered Organic Superconductors

Syuma Yasuzuka

doi:10.3390/cryst11060600

Abstract

Layered organic superconductors motivate intense investigations because they provide various unexpected issues associated with their low dimensionality and the strong electron correlation. Since layered organic superconductors possess simple Fermi surface geometry and they often share similarities to the high temperature oxide superconductors and heavy fermion compounds, research on layered organic superconductors is suitable for understanding the essence and nature of strongly correlated electron systems. In strongly correlated electron systems, one of the central problems concerning the superconducting (SC) state is the symmetry of the SC gap, which is closely related to the paring mechanism. Thus, experimental determination of the SC gap structure is of essential importance. In this review, we present the experimental results for the in-plane angular variation of the flux-flow resistance in layered organic superconductors k-(ET)2Cu(NCS)2, β″-(ET)2SF5CH2CF2SO3, and λ-(BETS)2GaCl4. The interplay between the vortex dynamics and nodal structures is discussed for these superconductors.

Highlights

Physics of organic conductors has provided the fascinating and rich issues associated with the low dimensionality and effect of electron correlation [1]
We have focused on the interplay between vortex dynamics and the SC
In order to discuss the relationship between vortex dynamics and the SC gap structure with d-wave paring symmetry, we investigated in-plane angular variation of vortex dynamics for the layered organic superconductors K-(ET)2 Cu(NCS)2, β”-(ET)2 SF5 CH2 CF2 SO3, and λ-(BETS)2 GaCl4

Summary

Introduction

Physics of organic conductors has provided the fascinating and rich issues associated with the low dimensionality and effect of electron correlation [1]. One of the most interesting systems are the layered organic conductors composed of the ET donor molecule, where ET denotes bis(ethylenedithio)tetrathiafulvalene. The ET donor molecules form two-dimensional (2D) conducting layers that are separated by insulating anion layers with a monovalent ion X−. The molecular structures of ET and BETS are shown in the upper right side of Figure 1a. There are several types (labeled by Greek letters) in packed ET donor layers. In the K type compounds, K-(ET) X, the measurements of Shubnikov-de Haas (SdH) and de Haas-van Alphen (dHvA)

Methods

Discussion

Conclusion