Vertical Line Nodes in the Superconducting Gap Structure of Sr2RuO4

The crystal Sr${}_{2}$RuO${}_{4}$ is a rare superconductor where electrons pair together in a symmetry that is thought to be a $p$ wave, which indicates how the electrons orbit one another and orient their spins. A new investigation of heat conduction in Sr${}_{2}$RuO${}_{4}$ reveals behavior more typical of a $d$ wave, raising questions about how the electrons are actually paired.