Superconductivity is an emergent phenomenon where the cooperative interactions between electrons give rise to a completely new state of matter with coherent entity. In a superconductor, the electrons lower their energy by moving in a synchronized way so that scattering by the ions and impurities, unavoidable in normal metals, cannot occur. As a result, superconductors lose their electrical resistance and can carry electricity without losses. This phenomenon is already more than one hundred years old. During this century, superconductivity has given many surprises and periods with a flurry of frenetic activity, where scientists and society alike looked forward to the dream of affordable superconducting applications.
One key event in the history of superconductivity was the discovery of the so-called type-II superconductors. The concept of type-II superconductivity based on the experimental results by Shubnikov (1936) and elaborated by A.A. Abrikosov (1957), received the Nobel Prize in Physics in 2003. In these materials, superconductivity survives to higher magnetic fields by allowing the field to enter as an array of quantized flux lines, the Abrikosov vortex lattice, with each vortex carrying a single flux quantum. Under the action of a current, vortices move and this motion produces non-zero resistance. Hence, the vortices need to be pinned in any practical application of superconductors. Understanding vortices in superconductors remains a challenging problem. All pinning mechanisms known so far become inefficient at high temperatures, just when they are most important for technological applications.
In the past few years, new and exciting discoveries include the iron pnictide materials, two-dimensional superconductors or strongly correlated heavy fermion materials. Furthermore, several studies show innovative methods to pin vortices and make known superconductors operational at higher magnetic fields and temperatures. Surface physics groups and materials scientists are studying the skyrmions, a magnetic structure with strong similarities to vortices. Vortices have been also observed in cold gases and in polariton condensates.
The goal of VORTEX 2015 is to contribute achieving the next quantum leap in superconductivity, with a significant improvement of their properties for applications, by gathering world leading scientists in vortex physics with scientists in other areas.
Emerging questions and unsolved problems
Topics included in the conference address vortex matter and mesoscopic superconductivity from different perspectives with the aim of solving present problems in the implementation of superconducting technology in operational devices. For example, how does vortex jamming proceed and how do dislocated vortex positions interact with pinning centers? What is the process behind unpinning when increasing temperature? What is the role of the temperature induced increased length scales of the superconductor? To answer these questions, we need to connect microscopic imaging with macroscopic transport experiments, by bringing together experts from both areas. But it will be also useful to understand dynamics of related systems such as the Skyrmion lattice, and investigate how dissipation appears in other kinds of condensates and in materials with exotic superconducting properties.
A few web pages and related YouTube channels:
- Low temperature Laboratory of UAM: Webpage and YouTube channel
- Youtube channel of the N. Cabrera Institute
- IFIMAC Institute
- Imdea Nano
- Universidad Complutense de Madrid
- Condensed matter group of the Spanish physics society: Webpage
- Other web pages of superconductivity: Superconductivity at ICMM
- APS Outreach project on Condensed Matter