Summary
Superconductivity is one of the most fascinating, macroscopically observable quantum phenomena. A notable aspect of its description is the existence of an attractive interaction, a “glue,” between electrons. This can bind them into Cooper pairs, which then condense into a common superconducting ground state. In contrast to conventional superconductors, which are described by the theory of Bardeen, Cooper, and Schrieffer, a primary phonon-mediated pairing mechanism is unlikely in the high-temperature (Tc) superconducting cuprates, and therefore they are referred to as unconventional. One characteristic of all high-Tc cuprates are the strong, quasi–two-dimensional antiferromagnetic correlations, with spin waves or magnons as possible alternative pairing glue. On page 213 of this issue, Lu et al. (1) report on antiferromagnetic magnon-like spin excitations in superconducting infinite-layer nickelate thin films.