From J$_{\mathrm{eff}}=$1/2 insulator to p-wave superconductor in single-crystal Sr$_{\mathrm{2}}$Ir$_{\mathrm{1-}}_{x}$Ru$_{x}$O$_{\mathrm{4}}$ (0 $\le $ x $\le $ 1)
ORAL
Abstract
Sr$_{\mathrm{2}}$IrO$_{\mathrm{4}}$ is a magnetic insulator assisted by strong spin-orbit coupling (SOC) whereas the Sr$_{\mathrm{2}}$RuO$_{\mathrm{4}}$ is a p-wave superconductor. Our investigation of structural, transport, and magnetic properties reveals that substituting 4d Ru$^{\mathrm{4+}}$ (4d$^{\mathrm{4}})$ ions for 5d Ir$^{\mathrm{4+}}$(5d$^{\mathrm{5}})$ ions in Sr$_{\mathrm{2}}$IrO$_{\mathrm{4}}$ directly adds holes to the t$_{\mathrm{2g}}$ bands, reduces the SOC and thus rebalances the competing energies in single-crystal Sr$_{\mathrm{2}}$Ir$_{\mathrm{1-x}}$Ru$_{\mathrm{x}}$O$_{\mathrm{4}}$. A profound effect of Ru doping driving a rich phase diagram is a structural phase transition from a distorted $I$4$_{\mathrm{1}}$/\textit{acd }to a more ideal $I$4/\textit{mmm }tetragonal structure near x$=$0.50 that accompanies a phase transition from an antiferromagnetic-insulating state to a paramagnetic-metal state. We also make a comparison drawn with Rh doped Sr$_{\mathrm{2}}$IrO$_{\mathrm{4}}$, highlighting important similarities and differences.
*This work was supported by the National Science Foundation via Grant No. DMR-1265162 and by Department of Energy (BES) through grant No. DE-FG02-98ER45707 (PS).
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