SmallTalks: Odd-frequency superconductivity in quantum materials

Abstract 

Superconductors are materials in which electrons can move without resistance. This remarkable behavior occurs because electrons form pairs, known as Cooper pairs. In most superconductors, these pairs can be described by asking how the two electrons are arranged in space and how their spins combine. However, quantum mechanics also allows a more unusual possibility: the pairing may depend on time in an essential way. This is called odd-frequency pairing.

In this talk, I will first introduce superconductivity and Cooper pairs using simple physical pictures. I will then explain why odd-frequency pairing is interesting and how it differs from conventional superconductivity. Finally, I will discuss a possible route to realizing this state in quantum materials, based on a coupling between lattice angular momentum and electron spin, and how interactions and fluctuations may help such pairing emerge.