Experimental bandstructure of the $5d$ transition metal oxide $IrO_2$

In the $5d$ iridium oxides the close energy scales of spin-orbit coupling and electron-electron correlations lead to emergent quantum phenomena. Much research has focused on the ternary iridium oxides, e.g. the Ruddlesden-Poppers $A_{n+1}B_{n}O_{3n+1}$, which exhibit behavior from metal to antiferromagnetic insulator ground states, share common features with the cuprates, and may host a number of topological phases. The binary rutile $IrO_2$ is another important $5d$ oxide, which has technological importance for spintronics due to its large spin Hall effect and also applications in catalysis. $IrO_2$ is expected to share similar physics as its perovskite-based cousins; however, due to bond-length distortions of the $IrO_6$ octahedra in the rutile structure, the extent of similarities remains an open question. Here we use angle-resolved photoemission spectroscopy to perform momentum-resolved measurements of the electronic structure of $IrO_2$. $IrO_2$ thin films were grown by molecular beam epitaxy on $TiO_2$ (110) substrates using an Ir e-beam source and distilled ozone. Films were subsequently transferred through ultrahigh vacuum to a connected ARPES system. Combined with first-principles calculations we explore the interplay of spin-orbit coupling and correlations in $IrO_2$.