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.

Controlled Nanoplatelet Deposition of 2D Chromium Trihalide Solid Solutions

“…After the sputtering process, no shrinkage of the Cr2p peaks was observed, but rather a small shoulder at lower binding energies appeared. This shoulder can be attributed to a partial reduction of Cr 3+ to Cr 2+ by the removal of Cl and Br from the surface and is described for similar materials in the literature . This observation denies the hypothesis of surface oxidation, confirming a pristine surface of the as-grown solid solution material.…”