A research team led by a Brown University physicist has produced new evidence for an exotic superconducting state, first predicted a half-century ago, that can indeed arise when a superconductor is exposed to a strong magnetic field.
Normally, a superconducting material has a roughly equal number of electrons with each spin, so nearly all electrons have a dance partner. “What happens with the ones that don’t have pairs? Can we actually form superconducting states that way, and what would that state look like?”.
This modulated superconductive state came to be known as the FFLO phase, named for theorists Peter Fulde, Richard Ferrell, Anatoly Larkin, and Yuri Ovchinniko, who predicted its existence.
The material consists of ultra-thin sheets stacked on top of each other and is exactly the kind of material predicted to exhibit the FFLO state. Experimentalists have been trying for years to provide solid evidence that the FFLO state exists, but to little avail.
More information: Evidence of Andreev bound states as a hallmark of the FFLO phase in κ-(BEDT-TTF)2Cu(NCS)2, Nature Physics, DOI: 10.1038/nphys3121.