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Title: Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations

Abstract

Electronic spectra of typical single FeSe layer superconductor—FeSe monolayer film on SrTiO{sub 3} substrate (FeSe/STO) obtained from ARPES data reveal several puzzles: what is the origin of shallow and the so called “replica” bands near the M-point and why the hole-like Fermi surfaces near the Γ-point are absent. Our extensive LDA+DMFT calculations show that correlation effects on Fe-3d states can almost quantitatively reproduce rather complicated band structure, which is observed in ARPES, in close vicinity of the Fermi level for FeSe/STO. Rather unusual shallow electron-like bands around the M-point in the Brillouin zone are well reproduced. Detailed analysis of the theoretical and experimental quasiparticle bands with respect to their origin and orbital composition is performed. It is shown that for FeSe/STO system the LDA calculated Fe-3d{sub xy} band, renormalized by electronic correlations within DMFT gives the quasiparticle band almost exactly in the energy region of the experimentally observed “replica” quasiparticle band at the Mpoint. However, correlation effects alone are apparently insufficient to eliminate the hole-like Fermi surfaces around the Γ-point, which are not observed in most ARPES experiments. The Fermi surfaces remain here even if Coulomb and/or Hund interaction strengths are increased while overall agreement with ARPES worsens. Increase ofmore » number of electrons also does not lead to vanishing of this Fermi surface and makes agreement of LDA+DMFT results with ARPES data much worse. We also present some simple estimates of “forward scattering” electron-optical phonon interaction at FeSe/STO interface, showing that it is apparently irrelevant for the formation of “replica” band in this system and significant increase of superconducting T{sub c}.« less

Authors:
; ;  [1]
  1. Russian Academy of Sciences, Institute of Electrophysics, Ural Branch (Russian Federation)
Publication Date:
OSTI Identifier:
22749902
Resource Type:
Journal Article
Journal Name:
Journal of Experimental and Theoretical Physics
Additional Journal Information:
Journal Volume: 126; Journal Issue: 4; Other Information: Copyright (c) 2018 Pleiades Publishing, Inc.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1063-7761
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BRILLOUIN ZONES; D STATES; ELECTRON CORRELATION; ELECTRONIC STRUCTURE; FERMI LEVEL; IRON SELENIDES; REPLICAS; STRONTIUM TITANATES

Citation Formats

Nekrasov, I. A., E-mail: nekrasov@iep.uran.ru, Pavlov, N. S., E-mail: pavlov@iep.uran.ru, and Sadovskii, M. V., E-mail: sadovski@iep.uran.ru. Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations. United States: N. p., 2018. Web. doi:10.1134/S1063776118040106.
Nekrasov, I. A., E-mail: nekrasov@iep.uran.ru, Pavlov, N. S., E-mail: pavlov@iep.uran.ru, & Sadovskii, M. V., E-mail: sadovski@iep.uran.ru. Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations. United States. doi:10.1134/S1063776118040106.
Nekrasov, I. A., E-mail: nekrasov@iep.uran.ru, Pavlov, N. S., E-mail: pavlov@iep.uran.ru, and Sadovskii, M. V., E-mail: sadovski@iep.uran.ru. Sun . "Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations". United States. doi:10.1134/S1063776118040106.
@article{osti_22749902,
title = {Electronic Structure of FeSe Monolayer Superconductors: Shallow Bands and Correlations},
author = {Nekrasov, I. A., E-mail: nekrasov@iep.uran.ru and Pavlov, N. S., E-mail: pavlov@iep.uran.ru and Sadovskii, M. V., E-mail: sadovski@iep.uran.ru},
abstractNote = {Electronic spectra of typical single FeSe layer superconductor—FeSe monolayer film on SrTiO{sub 3} substrate (FeSe/STO) obtained from ARPES data reveal several puzzles: what is the origin of shallow and the so called “replica” bands near the M-point and why the hole-like Fermi surfaces near the Γ-point are absent. Our extensive LDA+DMFT calculations show that correlation effects on Fe-3d states can almost quantitatively reproduce rather complicated band structure, which is observed in ARPES, in close vicinity of the Fermi level for FeSe/STO. Rather unusual shallow electron-like bands around the M-point in the Brillouin zone are well reproduced. Detailed analysis of the theoretical and experimental quasiparticle bands with respect to their origin and orbital composition is performed. It is shown that for FeSe/STO system the LDA calculated Fe-3d{sub xy} band, renormalized by electronic correlations within DMFT gives the quasiparticle band almost exactly in the energy region of the experimentally observed “replica” quasiparticle band at the Mpoint. However, correlation effects alone are apparently insufficient to eliminate the hole-like Fermi surfaces around the Γ-point, which are not observed in most ARPES experiments. The Fermi surfaces remain here even if Coulomb and/or Hund interaction strengths are increased while overall agreement with ARPES worsens. Increase of number of electrons also does not lead to vanishing of this Fermi surface and makes agreement of LDA+DMFT results with ARPES data much worse. We also present some simple estimates of “forward scattering” electron-optical phonon interaction at FeSe/STO interface, showing that it is apparently irrelevant for the formation of “replica” band in this system and significant increase of superconducting T{sub c}.},
doi = {10.1134/S1063776118040106},
journal = {Journal of Experimental and Theoretical Physics},
issn = {1063-7761},
number = 4,
volume = 126,
place = {United States},
year = {2018},
month = {4}
}