Coexistence of insulator-like paramagnon and metallic spin-orbit exciton
modes in SrIrO$_3$
Coexistence of insulator-like paramagnon and metallic spin-orbit exciton
modes in SrIrO$_3$
We probe the spectrum of elementary excitations in SrIrO$_3$ by using heterostructured [(SrIrO$_3$)$_m$/(SrTiO$_3$)$_l$] samples to approach the bulk limit. Our resonant inelastic x-ray scattering (RIXS) measurements at the Ir $L_3$-edge reveal a robust low-lying collective magnetic mode with an antiferromagnetic (AF) dispersion similar to the insulators Sr$_2$IrO$_4$ and Sr$_3$Ir$_2$O$_7$, albeit …