来源:ACS Publications
Deterministic control of the layering configuration of two-dimensional quantum materials plays a central role in studying their emergent electronic properties. Here we demonstrate in situ control over competing stacking configurations in thin film crystals of the rare-earth diantimonides by synthesizing in proximity to competing structural orders. A crossover between the epitaxially stabilized monoclinic structure and the orthorhombic structure commonly observed in bulk crystals is navigated through three axes─the relative cation/anion ratio, growth temperature, and choice of lanthanide ion─culminating with a comparative magnetotransport study of single-yet-distinct phase CeSb2 films. These results set the stage for an expanded search for hidden stacking configurations in layered compounds which have evaded detection.
In summary, we have demonstrated experimental control over competing stacking configurations of LnSb2 crystals grown as thin films. Bulk Sm-type and novel Yb-mono polymorphs are selectable in CeSb2 by tuning the flux ratio and substrate temperature during growth, and a crossover between these structures is supported by first-principles calculations. The unique ability to work across a wide range of Sb dosing conditions is revealed as important in driving the phase transition, which is inaccessible in conventional flux bulk synthesis. These results highlight the importance of thin film growth in discovering new structures in quantum materials otherwise inaccessible by traditional bulk-synthesis methods.