Dimensionality-strain phase diagram of strontium iridates

The competition between spin-orbit coupling, bandwidth (W), and electron-electron interaction (U) makes iridates highly susceptible to small external perturbations, which can trigger the onset of novel types of electronic and magnetic states. Here we employ first principles calculations based on density functional theory and on the constrained random phase approximation to study how dimensionality and strain affect the strength of U and W in (SrIrO3)(m)/(SrTiO3()) superlattices. The result is a phase diagram explaining two different types of controllable magnetic and electronic transitions, spin-flop and insulator-to-metal, connected with the disruption of the J(eff) = 1/2 state which cannot be understood within a simplified local picture.