Electronic coupling between a FeSe monolayer film and substrate
- 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
- Univ. of California, Davis, CA (United States). Dept. of Physics
Several experimental groups have reported superconductivity in single unit cell layers of FeSe on SrTiO3 and a few other substrates, with critical temperature $$T_c$$ reports ranging up to 100 K, and a variety of theoretical work has been done. In this work 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($$\hat{z}$$)] 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($$\hat{z}$$) 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.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC); China Scholarship Council (CSC); National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-05CH11231; DMR 1607139
- OSTI ID:
- 1544398
- Alternate ID(s):
- OSTI ID: 1349961
- Journal Information:
- Physical Review B, Vol. 95, Issue 16; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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