Strong surface termination dependence of the electronic structure of polar superconductor LaFeAsO revealed by nano-ARPES

The electronic structures of the iron-based superconductors have been intensively studied by using angle-resolved photoemission spectroscopy (ARPES). A considerable amount of research has been focused on the LaFeAsO family, showing the highest transition temperatures, where previous ARPES studies ha...

Full description

Saved in:
Bibliographic Details
Published in:New journal of physics 2022-11, Vol.24 (11), p.113018
Main Authors: Jung, Sung Won, Rhodes, Luke C, Watson, Matthew D, Evtushinsky, Daniil V, Cacho, Cephise, Aswartham, Saicharan, Kappenberger, Rhea, Wurmehl, Sabine, Büchner, Bernd, Kim, Timur K
Format: Article
Language:English
Subjects:
Electronic structure
Fermi surfaces
Ion beams
iron-based superconductors
Photoelectric emission
Photoelectron spectroscopy
photoemission
Physics
polar surface
Spectrum analysis
Superconductors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The electronic structures of the iron-based superconductors have been intensively studied by using angle-resolved photoemission spectroscopy (ARPES). A considerable amount of research has been focused on the LaFeAsO family, showing the highest transition temperatures, where previous ARPES studies have found much larger Fermi surfaces than bulk theoretical calculations would predict. The discrepancy has been attributed to the presence of termination-dependent surface states. Here, using photoemission spectroscopy with a sub-micron focused beam spot (nano-ARPES) we have successfully measured the electronic structures of both the LaO and FeAs terminations in LaFeAsO. Our data reveal very different band dispersions and core-level spectra for different surface terminations, showing that previous macro-focus ARPES measurements were incomplete. Our results give direct evidence for the surface-driven electronic structure reconstruction in LaFeAsO, including formation of the termination-dependent surface states at the Fermi level. This experimental technique, which we have shown to be very powerful when applied to this prototypical compound, can now be used to study various materials with different surface terminations.
ISSN:1367-2630
1367-2630
DOI:10.1088/1367-2630/ac9d5e