Rutile RuO2 has attracted significant interest due to its putative unconventional electronic and magnetic properties and its proximity to superconductivity. However, the measurement and interpretation of its electronic structure has been complicated by a strongly three-dimensional crystal structure. Here, we demonstrate how the preparation of targeted (110) and (100) surfaces via focused ion beam (FIB)-engineered cleaving allows the acquisition of high-quality measurements of the electronic structure using angle-resolved photoemission spectroscopy. Our results demonstrate that ARPES spectra of RuO2 are, in fact, largely dominated by signatures of distinct surface electronic states. From comparison with density-functional theory, we resolve a surface termination-dependent variation of these, and disentangle them from highly-three-dimensional bulk states and surface resonances. Moreover, we find a marked role of the substantial spin-orbit coupling of the Ru 4d orbitals in the surface region, where a breaking of spatial inversion symmetry leads to significant Rashba-type spin splittings of the surface bands.
@article{arxiv.2605.06798,
title = {Disentangling bulk and surface electronic structure using targeted cleave planes in RuO$_2$},
author = {Maria H. Visscher and Sebastian Buchberger and Bruno Saika and Shu Mo and Lea Richter and Mats Leandersson and Craig Polley and Andrew P. Mackenzie and Phil D. C. King},
journal= {arXiv preprint arXiv:2605.06798},
year = {2026}
}