One of the most spectacular consequences of the description of the superfluid condensate in superfluid He or in superconductors as a single macroscopic quantum state is the quantization of circulation, resulting in quantized vortex lines. This book draws no distinction between superfluid He3 and He4 and superconductors. The reader will find the essential introductory chapters and the most recent theoretical and experimental progress in our understanding of the vortex state in both superconductors and superfluids, from lectures given by leading experts in the field, both experimentalists and theoreticians, who gathered in Cargèse for a NATO ASI. The peculiar features related to short coherence lengths, 2D geometry, high temperatures, disorder, and pinning are thoroughly discussed.

Studies of High Temperature Superconductors, Volume 48 - Vortex Physics & Flux Pinning

In the last decades, superconducting devices have emerged as a promising platform for quantum technologies, including quantum sensing and quantum computing. Their key elements are Josephson junctions, which allow for coherent supercurrent tunneling between two weakly linked superconductors. If such a junction is extended in one direction to a long junction, the superconducting phase difference can vary in space and time and may allow for quantized phase windings that drive supercurrent vortices.

This report documents the design and construction of a low temperature scanning tunneling microscope optimized for the study of superconductors. The microscope was first used to study the vortex liquid state in the cuprate high-Tc superconductor Bi2Sr2Cu06+x. This work distinguished between a homogenous superconducting gap and an additional inhomogenous 'pseudogap' which may be linked to an alternative electronic ordered state. The microscope then performed the first atomic resolution, high-field investigation of the new iron arsenic high-Tc superconductors. In particular, the vortex state was mapped in Ba(CoxFe1-x)2As2. Vortices formed a disordered lattice, uncorrelated with surface impurities, which demonstrated strong bulk pinning. Vortex core states were used to measure an electronic correlation length of 2.8 nanometers, from which an upper critical field of 43 Tesla was calculated.

Studies of High Temperature Superconductors, Volume 42 - Vortex Physics