Atomic-scale visualization of surface-assisted orbital order.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28948229.
- Also identified by DOI 10.1126/sciadv.aao0362 and PMC identifier 5609848.
- Licence recorded as CC BY-NC.
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Abstract
Orbital-related physics attracts growing interest in condensed matter research, but direct real-space access of the orbital degree of freedom is challenging. We report a first, real-space, imaging of a surface-assisted orbital ordered structure on a cobalt-terminated surface of the well-studied heavy fermion compound CeCoIn<sub>5</sub>. Within small tip-sample distances, the cobalt atoms on a cleaved (001) surface take on dumbbell shapes alternatingly aligned in the [100] and [010] directions in scanning tunneling microscopy topographies. First-principles calculations reveal that this structure is a consequence of the staggered d <sub><i>xz</i></sub> -d <sub><i>yz</i></sub> orbital order triggered by enhanced on-site Coulomb interaction at the surface. This so far overlooked surface-assisted orbital ordering may prevail in transition metal oxides, heavy fermion superconductors, and other materials.