Abstract
The discovery of an enhanced superconducting transition temperature Tc in monolayers of FeSe grown on several oxide substrates has opened a different route to high-Tc superconductivity through interface engineering. One proposal for the origin of the observed enhancement is an electron-phonon (e-ph) interaction across the interface that is peaked at small momentum transfers. In this paper, we examine the implications of such a coupling on the phononic properties of the system. We show that a strong forward scattering leads to a sizable broadening of phonon line shape, which may result in charge instabilities at long wavelengths. However, we further find that the inclusion of Coulombic screening significantly reduces the phonon broadening. Our results show that one might not expect anomalously broad phonon linewidths in the FeSe interface systems, despite the fact that the e-ph interaction has a strong peak in the forward-scattering (small q) direction.
| Original language | English |
|---|---|
| Article number | 054515 |
| Journal | Physical Review B |
| Volume | 96 |
| Issue number | 5 |
| DOIs | |
| State | Published - Aug 18 2017 |
| Externally published | Yes |
Funding
We thank T. Berlijn, T. P. Devereaux, M. L. Kulić, E. W. Plummer, and D. J. Scalapino for useful discussions. L.R. acknowledges funding from the Dutch Science Foundation (NWO) via a Rubicon Fellowship and by the National Science Foundation under Grants No. PHY11-25915 and No. NSF-KITP-17-019. S.J. was supported by the University of Tennessee's Office of Research and Engagement's Organized Research Unit program. Y.W. and E.D. were supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. This research used computational resources supported by the University of Tennessee and Oak Ridge National Laboratory's Joint Institute for Computational Sciences.