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arXiv · 1703.04021

Dipolar phonons and electronic screening in monolayer FeSe on SrTiO$_3$

Yuanjun Zhou·Andrew J. Millis
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Abstract

Monolayer films of FeSe grown on SrTiO$_3$ substrates exhibit significantly higher superconducting transition temperatures than those of bulk FeSe. Interaction of electrons in the FeSe layer with dipolar SrTiO$_3$ phonons has been suggested as the cause of the enhanced transition temperature. In this paper we systematically study the coupling of SrTiO$_3$ 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 SrTiO$_3$ 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.

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Yuanjun Zhou, Andrew J. Millis. 2017-03-11. Dipolar phonons and electronic screening in monolayer FeSe on SrTiO$_3$. https://doi.org/10.1103/physrevb.96.054516

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