Monolayer films of FeSe grown on SrTiO3 substrates exhibit significantly higher superconducting transition temperatures than those of bulk FeSe. Interaction of electrons in the FeSe layer with dipolar SrTiO3 phonons has been suggested as the cause of the enhanced transition temperature. In this paper we systematically study the coupling of SrTiO3 longitudinal optical phonons to the FeSe electron, including also electron-electron Coulomb interactions at the random phase approximation level. We find that the electron-phonon interaction between FeSe and SrTiO3 substrate is almost entirely screened by the electronic fluctuations in the FeSe monolayer, so that the net electron-phonon interaction is very weak and unlikely to lead to superconductivity.
@article{arxiv.1703.04021,
title = {Dipolar phonons and electronic screening in monolayer FeSe on SrTiO$_3$},
author = {Yuanjun Zhou and Andrew J. Millis},
journal= {arXiv preprint arXiv:1703.04021},
year = {2017}
}