Fermi arcs in a doped pseudospin-1/2 Heisenberg antiferromagnet

Identifying a cuprate look-alike Superconductivity in cuprate compounds remains poorly understood. Recreating its features in an unrelated material may provide insight. Kim et al. used a spectroscopic technique to study the electronic states of the material Sr2IrO4 at relatively high temperatures. They observed phenomenology similar to that of cuprates as they varied the surface carrier concentration. The study highlights the essential properties a material needs in order to exhibit cuprate-like features in the normal (nonsuperconducting) state. Science, this issue p. 187 Some of the phenomenology of cuprate superconductors is recreated in strontium iridate surface-doped with potassium. High-temperature superconductivity in cuprates arises from an electronic state that remains poorly understood. We report the observation of a related electronic state in a noncuprate material, strontium iridate (Sr2IrO4), in which the distinct cuprate fermiology is largely reproduced. Upon surface electron doping through in situ deposition of alkali-metal atoms, angle-resolved photoemission spectra of Sr2IrO4 display disconnected segments of zero-energy states, known as Fermi arcs, and a gap as large as 80 millielectron volts. Its evolution toward a normal metal phase with a closed Fermi surface as a function of doping and temperature parallels that in the cuprates. Our result suggests that Sr2IrO4 is a useful model system for comparison to the cuprates.