Nickel Age of High-Temperature Superconductivity

Unconventional high-temperature superconductivity has long been a fascinating puzzle in condensed matter physics. The 1987 Nobel Prize in Physics recognized the discovery of high-temperature superconductivity in copper oxide ceramics. Nearly four decades later, the demonstration of a broader class of high-temperature superconducting oxides, along with a fundamental understanding of the pairing mechanism, remains elusive. Recently, nickel oxides have emerged as a new class of high-temperature superconductors beyond copper, where correlated phases can be controlled by doping, pressure, and dimensionality. In this talk, we present the observation of unconventional spin-symmetric Cooper pairs, broken time-reversal pairing symmetry, and superconductivity with a critical temperature above 35 K in infinite-layer nickelates. We will also discuss recent developments and the future outlook of the nickel age of high-temperature superconductivity.