Smart superconductors are predicted to fundamentally change our everyday lives. Computers millions of times faster than today's, super-efficient electric transport and a worldwide fleet of levitating magnetic trains are just some of the achievements that could become reality. But to fully exploit these materials, we need to better understand the underlying mechanisms of superconductors.
In a recent study, a team of researchers investigated the superconductor NbSe₂ (niobium diselenide). Using small-angle neutron scattering, the researchers found that the material has properties that were previously unknown. Among other things, they found that NbSe₂ contains two independent superconducting bands that can both conduct electricity without resistance, something that had previously been disputed. This makes the material a more efficient superconductor with a broader range of applications.
"The study helps to refine theoretical models of superconductivity, but it also provides completely new insights into how the coupling between the independent bands affects the superconducting properties," says Ahmed Alshemi, a physics researcher at Lund University.
In the study, the researchers were able to show how the material NbSe₂ becomes superconducting at very low temperatures. They were also able to show for the first time how different parts of the electron structure interact - and how this affects the material's properties.
"Our results provide a deeper perspective on how different electron bands interact and affect superconductivity in complex materials," says Ahmed Alshemi.
A piece of the technological puzzle
There has been a long-standing debate among physicists about how multiple electron bands affect the properties of a superconductor. In particular, how these bands affect the material's ability to recover from defects has been discussed. The research team has now established that this “repairing” property is due to a specific feature of the electron band.
"Studies and analyses of this type of superconductor could pave the way for new materials. These can have customised properties that will be used in the future in everything from energy-efficient minicomputers to cutting-edge medical technology," says Ahmed Alshemi.
In addition to Lund University, the following universities have participated in the work: University of Birmingham, Institut Laue Langevin, European Spallation Source, PSI Centre for Neutron and Muon Sciences, Forschungszentrum Jülich.
The study is published in the scientific journal Physical Review Letters: ‘Two Characteristic Contributions to the Superconducting State of 2H-NbS₂’.
Ahmed Alshemi's profile in the Lund University research portal.