When superconductivity crosses over: From BCS to BEC
Qijin Chen, Zhiqiang Wang, Rufus Boyack +2 more
The theory of unconventional superconductors continues to provide profound puzzles. The crossover between the weakly coupled Bardeen-Cooper-Schrieffer (BCS) state and the strong-pairing Bose-Einstein condensate (BEC) provides a useful perspective on how to address these questions. This paper describes a self-consistent framework for thinking about the crossover regime in between these two limits. The review discusses to what extent this BCS-BEC theory applies to a range of classes of superconducting materials including the cuprates, iron pnictides, twisted bilayer graphene, and interfacial superconductivity among others.
arXiv:2208.01774•Reviews of Modern Physics•May 23, 2024•64 citations