Physicists just found the ‘ghost’ of superconductivity

Physicists at the University of Illinois Urbana-Champaign's Grainger College of Engineering have uncovered evidence of an unusual form of superconducting behavior in uranium ditelluride. Their experiments show that Cooper pairs, the paired electrons that make superconductivity possible, can arrange themselves into uneven patterns even when the material is no longer in its main superconducting state.

These patterns are called pair density waves (PDWs). Scientists first predicted them about 20 years ago, and previous studies have observed them alongside superconductivity in other metals. The new research, published in the Proceedings of the National Academy of Sciences , goes further. It provides the first direct evidence that PDWs in uranium ditelluride can remain in the material's "ordinary" phase after superconductivity has disappeared.