Ab initio study of cross-interface electron-phonon couplings in FeSe thin films on and
Abstract
We study the electron-phonon coupling strength near the interface of monolayer and bilayer FeSe thin films on SrTiO 3 , BaTiO 3 , and oxygen-vacant SrTiO 3 substrates, using ab initio methods. The calculated total electron-phonon coupling strength λ = 0.2 – 0.3 cannot account for the high T c ~ 70 K observed in these systems through the conventional phonon-mediated pairing mechanism. In all of these systems, however, we find that the coupling constant of a polar oxygen branch peaks at q = 0 with negligible coupling elsewhere, while the energy of this mode coincides with the offset energy of the replica bands measured recently by angle-resolved photoemission spectroscopy experiments. However, the integrated coupling strength for this mode from our current calculations is still too small to produce the observed high T c , even through the more efficient pairing mechanism provided by the forward scattering. Also, we arrive at the same qualitative conclusion when considering a checkerboard antiferromagnetic configuration in the Fe layer. In light of the experimental observations of the replica band feature and the relatively high T c of FeSe monolayers on polar substrates, our results point towards a cooperative role for the electron-phonon interaction, wheremore »
- Authors:
-
[3];
- Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
- Univ. of Florida, Gainesville, FL (United States). Dept. of Physics
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences, Computer Science and Mathematics Division
- Publication Date:
- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1393894
- Alternate Identifier(s):
- OSTI ID: 1249680
- Grant/Contract Number:
- AC05-00OR22725; FG02-05ER46236
- Resource Type:
- Journal Article: Accepted Manuscript
- Journal Name:
- Physical Review B
- Additional Journal Information:
- Journal Volume: 93; Journal Issue: 13; Journal ID: ISSN 2469-9950
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Citation Formats
Wang, Y., Linscheid, A., Berlijn, T., and Johnston, S. Ab initio study of cross-interface electron-phonon couplings in FeSe thin films on SrTiO3 and BaTiO3. United States: N. p., 2016.
Web. doi:10.1103/PhysRevB.93.134513.
Wang, Y., Linscheid, A., Berlijn, T., & Johnston, S. Ab initio study of cross-interface electron-phonon couplings in FeSe thin films on SrTiO3 and BaTiO3. United States. doi:10.1103/PhysRevB.93.134513.
Wang, Y., Linscheid, A., Berlijn, T., and Johnston, S. Fri .
"Ab initio study of cross-interface electron-phonon couplings in FeSe thin films on SrTiO3 and BaTiO3". United States. doi:10.1103/PhysRevB.93.134513. https://www.osti.gov/servlets/purl/1393894.
@article{osti_1393894,
title = {Ab initio study of cross-interface electron-phonon couplings in FeSe thin films on SrTiO3 and BaTiO3},
author = {Wang, Y. and Linscheid, A. and Berlijn, T. and Johnston, S.},
abstractNote = {We study the electron-phonon coupling strength near the interface of monolayer and bilayer FeSe thin films on SrTiO 3 , BaTiO 3 , and oxygen-vacant SrTiO 3 substrates, using ab initio methods. The calculated total electron-phonon coupling strength λ = 0.2 – 0.3 cannot account for the high T c ~ 70 K observed in these systems through the conventional phonon-mediated pairing mechanism. In all of these systems, however, we find that the coupling constant of a polar oxygen branch peaks at q = 0 with negligible coupling elsewhere, while the energy of this mode coincides with the offset energy of the replica bands measured recently by angle-resolved photoemission spectroscopy experiments. However, the integrated coupling strength for this mode from our current calculations is still too small to produce the observed high T c , even through the more efficient pairing mechanism provided by the forward scattering. Also, we arrive at the same qualitative conclusion when considering a checkerboard antiferromagnetic configuration in the Fe layer. In light of the experimental observations of the replica band feature and the relatively high T c of FeSe monolayers on polar substrates, our results point towards a cooperative role for the electron-phonon interaction, where the cross-interface interaction acts in conjunction with a purely electronic interaction. Finally, we discuss a few scenarios where the coupling strength obtained here may be enhanced.},
doi = {10.1103/PhysRevB.93.134513},
journal = {Physical Review B},
issn = {2469-9950},
number = 13,
volume = 93,
place = {United States},
year = {2016},
month = {4}
}
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