TY - JOUR
T1 - Strong surface termination dependence of the electronic structure of polar superconductor LaFeAsO revealed by nano-ARPES
AU - Jung, Sung Won
AU - Rhodes, Luke C
AU - Watson, Matthew D
AU - Evtushinsky, Daniil V
AU - Cacho, Cephise
AU - Aswartham, Saicharan
AU - Kappenberger, Rhea
AU - Wurmehl, Sabine
AU - Büchner, Bernd
AU - Kim, Timur K
N1 - Funding: LCR acknowledges funding from the Royal Commission for the Exhibition of 1851. The work at IFW was supported by the Deutsche Forschungsgemeinschaft (DFG) through the Priority Program SPP1458. SA thanks the DFG for funding (AS 523∖4-1 & 523∖3-1).
PY - 2022/11/10
Y1 - 2022/11/10
N2 - 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.
AB - 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.
KW - Iron-based superconductors
KW - Photoemission
KW - Electronic structure
KW - Polar surface
UR - https://www.scopus.com/pages/publications/85142497236
U2 - 10.1088/1367-2630/ac9d5e
DO - 10.1088/1367-2630/ac9d5e
M3 - Article
SN - 1367-2630
VL - 24
JO - New Journal of Physics
JF - New Journal of Physics
IS - 11
M1 - 113018
ER -