High-order replica bands in monolayer FeSe/SrTiO<sub>3</sub> revealed by polarization-dependent photoemission spectroscopy.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34321473.
- Also identified by DOI 10.1038/s41467-021-24783-5 and PMC identifier 8319137.
- 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
The mechanism of the enhanced superconductivity in monolayer FeSe/SrTiO<sub>3</sub> has been enthusiastically studied and debated over the past decade. One specific observation has been taken to be of central importance: the replica bands in the photoemission spectrum. Although suggestive of electron-phonon interaction in the material, the essence of these spectroscopic features remains highly controversial. In this work, we conduct angle-resolved photoemission spectroscopy measurements on monolayer FeSe/SrTiO<sub>3</sub> using linearly polarized photons. This configuration enables unambiguous characterization of the valence electronic structure with a suppression of the spectral background. We consistently observe high-order replica bands derived from various Fe 3d bands, similar to those observed on bare SrTiO<sub>3</sub>. The intensity of the replica bands is unexpectedly high and different between d<sub>xy</sub> and d<sub>yz</sub> bands. Our results provide new insights on the electronic structure of this high-temperature superconductor and the physical origin of the photoemission replica bands.