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Title: The role of double TiO 2 layers at the interface of FeSe/SrTiO 3 superconductors

We determine the surface reconstruction of SrTiO 3 used to achieve superconducting FeSe films in experiments, which is different from the 1×1 TiO 2-terminated SrTiO 3 assumed by most previous theoretical studies. In particular, we identify the existence of a double TiO 2 layer at the FeSe/SrTiO 3 interface that plays two important roles. First, it facilitates the epitaxial growth of FeSe. Second, ab initio calculations reveal a strong tendency for electrons to transfer from an oxygen deficient SrTiO 3 surface to FeSe when the double TiO 2 layer is present. The double layer helps to remove the hole pocket in the FeSe at the Γ point of the Brillouin zone and leads to a band structure characteristic of superconducting samples. The characterization of the interface structure presented here is a key step towards the resolution of many open questions about this superconductor.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1] ;  [3] ;  [1] ;  [1] ;  [1]
  1. Yale Univ., New Haven, CT (United States)
  2. Yale Univ., New Haven, CT (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Fudan Univ., Shanghai (China)
Publication Date:
Report Number(s):
BNL-112212-2016-JA
Journal ID: ISSN 2469-9950; PRBMDO; R&D Project: MA509MACA; KC0203020; TRN: US1601742
Grant/Contract Number:
SC0012704
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; Journal Issue: 18; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1255726
Alternate Identifier(s):
OSTI ID: 1253228

Zou, Ke, Bozovic, Ian, Mandal, Subhasish, Albright, Stephen, Peng, Rui, Kumah, Divine, Simon, Georg, Dagdeviren, Omur, He, Xi, Schwarz, Udo, Altman, Eric, Feng, Donglai, Walker, F. J., Ismail-Geigi, Sohrab, and Ahn, C. H.. The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors. United States: N. p., Web. doi:10.1103/PhysRevB.93.180506.
Zou, Ke, Bozovic, Ian, Mandal, Subhasish, Albright, Stephen, Peng, Rui, Kumah, Divine, Simon, Georg, Dagdeviren, Omur, He, Xi, Schwarz, Udo, Altman, Eric, Feng, Donglai, Walker, F. J., Ismail-Geigi, Sohrab, & Ahn, C. H.. The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors. United States. doi:10.1103/PhysRevB.93.180506.
Zou, Ke, Bozovic, Ian, Mandal, Subhasish, Albright, Stephen, Peng, Rui, Kumah, Divine, Simon, Georg, Dagdeviren, Omur, He, Xi, Schwarz, Udo, Altman, Eric, Feng, Donglai, Walker, F. J., Ismail-Geigi, Sohrab, and Ahn, C. H.. 2016. "The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors". United States. doi:10.1103/PhysRevB.93.180506. https://www.osti.gov/servlets/purl/1255726.
@article{osti_1255726,
title = {The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors},
author = {Zou, Ke and Bozovic, Ian and Mandal, Subhasish and Albright, Stephen and Peng, Rui and Kumah, Divine and Simon, Georg and Dagdeviren, Omur and He, Xi and Schwarz, Udo and Altman, Eric and Feng, Donglai and Walker, F. J. and Ismail-Geigi, Sohrab and Ahn, C. H.},
abstractNote = {We determine the surface reconstruction of SrTiO3 used to achieve superconducting FeSe films in experiments, which is different from the 1×1 TiO2-terminated SrTiO3 assumed by most previous theoretical studies. In particular, we identify the existence of a double TiO2 layer at the FeSe/SrTiO3 interface that plays two important roles. First, it facilitates the epitaxial growth of FeSe. Second, ab initio calculations reveal a strong tendency for electrons to transfer from an oxygen deficient SrTiO3 surface to FeSe when the double TiO2 layer is present. The double layer helps to remove the hole pocket in the FeSe at the Γ point of the Brillouin zone and leads to a band structure characteristic of superconducting samples. The characterization of the interface structure presented here is a key step towards the resolution of many open questions about this superconductor.},
doi = {10.1103/PhysRevB.93.180506},
journal = {Physical Review B},
number = 18,
volume = 93,
place = {United States},
year = {2016},
month = {5}
}