Influence of Orbital Character on the Ground State Electronic Properties in the van Der Waals Transition Metal Iodides VI<sub>3</sub> and CrI<sub>3</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36039834.
- Also identified by DOI 10.1021/acs.nanolett.2c01922 and PMC identifier 9479147.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Two-dimensional van der Waals magnetic semiconductors display emergent chemical and physical properties and hold promise for novel optical, electronic and magnetic "few-layers" functionalities. Transition-metal iodides such as CrI<sub>3</sub> and VI<sub>3</sub> are relevant for future electronic and spintronic applications; however, detailed experimental information on their ground state electronic properties is lacking often due to their challenging chemical environment. By combining X-ray electron spectroscopies and first-principles calculations, we report a complete determination of CrI<sub>3</sub> and VI<sub>3</sub> electronic ground states. We show that the transition metal-induced orbital filling drives the stabilization of distinct electronic phases: a wide bandgap in CrI<sub>3</sub> and a Mott insulating state in VI<sub>3</sub>. Comparison of surface-sensitive (angular-resolved photoemission spectroscopy) and bulk-sensitive (X-ray absorption spectroscopy) measurements in VI<sub>3</sub> reveals a surface-only V<sup>2+</sup> oxidation state, suggesting that ground state electronic properties are strongly influenced by dimensionality effects. Our results have direct implications in band engineering and layer-dependent properties of two-dimensional systems.