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Title: Electronic coupling between a FeSe monolayer film and SrTiO 3 substrate

Abstract

Several experimental groups have reported superconductivity in single unit cell layers of FeSe on SrTiO3 and a few other substrates, with critical temperature Tc reports ranging up to 100 K, and a variety of theoretical work has been done. Here we examine more closely the interaction of a single FeSe layer with a TiO2 terminated SrTiO3(001) (STO) substrate. Several situations are analyzed: the underlying ideal interface, the effect of zpolarized longitudinal optic [LO(ˆz )] phonons in STO, electron doping of the STO substrate, substitution of Se by the bordering chalcogenides S and Te, and doping by adsorption of K on the FeSe surface. These results complement earlier studies of O and Se vacancies. The O py,py surface band of STO persists at the interface, and by sharing holes with the hole pocket of FeSe it plays a part in the behavior around the interface, initially by determining the Fe Fermi level lineup with the STO band gap. The LO(ˆz) mode causes strong band shifts around the interface but the strength of coupling to the Fe bands cannot be obtained with our methods. Adsorption of 25% K (one K per four Fe) fills the small O interface hole pocket and donatesmore » the rest of the electrons to the Fe hole pockets, filling them.« less

Authors:
 [1];  [2]
  1. Chinese Academy of Sciences (CAS), Beijing (China). Key Lab. of Materials Physics; Univ. of Science and Technology of China, Hefei (China); Univ. of California, Davis, CA (United States). Dept. of Physics
  2. Univ. of California, Davis, CA (United States). Dept. of Physics
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1544398
DOE Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 16; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

Citation Formats

Huang, Y. N., and Pickett, W. E. Electronic coupling between a FeSe monolayer film and SrTiO3 substrate. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.165107.
Huang, Y. N., & Pickett, W. E. Electronic coupling between a FeSe monolayer film and SrTiO3 substrate. United States. doi:10.1103/PhysRevB.95.165107.
Huang, Y. N., and Pickett, W. E. Sat . "Electronic coupling between a FeSe monolayer film and SrTiO3 substrate". United States. doi:10.1103/PhysRevB.95.165107.
@article{osti_1544398,
title = {Electronic coupling between a FeSe monolayer film and SrTiO3 substrate},
author = {Huang, Y. N. and Pickett, W. E.},
abstractNote = {Several experimental groups have reported superconductivity in single unit cell layers of FeSe on SrTiO3 and a few other substrates, with critical temperature Tc reports ranging up to 100 K, and a variety of theoretical work has been done. Here we examine more closely the interaction of a single FeSe layer with a TiO2 terminated SrTiO3(001) (STO) substrate. Several situations are analyzed: the underlying ideal interface, the effect of zpolarized longitudinal optic [LO(ˆz )] phonons in STO, electron doping of the STO substrate, substitution of Se by the bordering chalcogenides S and Te, and doping by adsorption of K on the FeSe surface. These results complement earlier studies of O and Se vacancies. The O py,py surface band of STO persists at the interface, and by sharing holes with the hole pocket of FeSe it plays a part in the behavior around the interface, initially by determining the Fe Fermi level lineup with the STO band gap. The LO(ˆz) mode causes strong band shifts around the interface but the strength of coupling to the Fe bands cannot be obtained with our methods. Adsorption of 25% K (one K per four Fe) fills the small O interface hole pocket and donates the rest of the electrons to the Fe hole pockets, filling them.},
doi = {10.1103/PhysRevB.95.165107},
journal = {Physical Review B},
issn = {2469-9950},
number = 16,
volume = 95,
place = {United States},
year = {2017},
month = {4}
}

Works referenced in this record:

Generalized Gradient Approximation Made Simple
journal, October 1996

  • Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
  • Physical Review Letters, Vol. 77, Issue 18, p. 3865-3868
  • DOI: 10.1103/PhysRevLett.77.3865