Visualizing pair formation on the atomic scale in the high-Tc superconductor Bi2Sr2CaCu2O8+δ

Two papers in this issue report notable contributions towards an understanding of high-temperature superconductivity, still an elusive goal after more than 20 years of intensive research. Doiron-Leyraud et al. report the observation of a Fermi surface in a high-temperature superconductor, a phenomenon regarded as the classic signature of a metal. Gomes et al. tackled the long-standing question of whether the gap in the electronic energy spectrum at temperatures above the critical temperature of a high-temperature superconductor is associated with electron pairing. They find that it is. With these two elegant experimental papers adding some solid new data to the mix, it is the turn of the theorists to work out the implications for superconductivity mechanisms.