Hard and soft x-ray photoemission spectroscopy study of the new Kondo system SmO thin film

Abstract

SmO thin film is a new Kondo system showing a resistivity upturn around 10 K and was theoretically proposed to have a topologically nontrivial band structure. We have performed hard x-ray and soft x-ray photoemission spectroscopy to elucidate the electronic structure of SmO. From the Sm 3$d$ core-level spectra, we have estimated the valence of Sm to be $\sim$2.96, proving that the Sm has a mixed valence. The valence-band photoemission spectra exhibit a clear Fermi edge originating from the Sm 5$d$-derived band. The present finding is consistent with the theory suggesting a possible topological state in SmO and show that rare-earth monoxides or their heterostructures can be a new playground for the interplay of strong electron correlation and spin-orbit coupling.

References in corpus (5)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• Correlated Topological Insulators with Mixed Valence
• Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
• Topological properties and the dynamical crossover from mixed-valence to Kondo-lattice behavior in golden phase of SmS
• SmO thin films: a flexible route to correlated flat bands with nontrivial topology