Work Function Engineering of Thin α‐RuCl3 by Argon Sputtering

Abstract

Abstractα‐RuCl3 is a candidate material for the realization of a Kitaev spin liquid with envisioned applications for quantum computing. It is a van‐der‐Waals material with in‐plane honeycomb lattice equivalent to the CrX3 (X= Cl, Br, I) type 2D magnets. Here, possibilities of defect engineering and surface modification of thin crystals are explored by Ar+ dosing and vacuum annealing. Chlorine is easily removed from the surface, which reduces the Ru valence and eventually leaves a Ru rich surface layer behind. A peculiar thickness dependence of the work function emerges after Ar+ sputtering, which is ascribed to the remaining chlorine concentration. This work elucidates material properties of thin α‐RuCl3 and introduces concepts of property engineering to create homojunctions and control level alignment by standard in situ methods.