Title: Dimensionality-strain phase diagram of strontium iridates,
Abstract: 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 {\em 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 (SrIrO$_3$)$_m$/(SrTiO$_3$) 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 cannnot be understood within a
simplified local picture.