A DFT+DMFT Investigation on Electron-Phonon Coupling in FeSe

ORAL

Abstract

The dramatic increase of superconducting temperature with external pressure in undoped FeSe has opened up a new route to investigate the mechanism of superconductivity. Using the self-consistent density functional theory-dynamical mean field theory (DFT-DMFT) method for paramagnetic FeSe as a function of compression, we find that there is greatly enhanced coupling between some correlated electron states between $\Gamma$ and Z points and the $A_{1g}$ lattice distortion. Except at high pressure, the maximum deformation potential in DFT for this mode is insensitive to increasing pressure, whereas the corresponding DFT-DMFT maximum deformation potential shows the same behavior with pressure as the experimental $T_c$, which first increases and then decreases with pressure. The Fermi surface average of the deformation potential in DFT-DMFT method can increase up to 50\% when compared to standard DFT

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Authors

  • Subhasish Mandal

    Geophysical Laboratory, Carnegie Institution of Washington, Washington D.C. 20015, USA

  • R.E. Cohen

    Geophysical Laboratory, Carnegie Institution of Washington, Washington D.C. 20015, USA, Geophysical Lab, Carnegie Institution of Washington, Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd., NW, Washington DC20015

  • Kristjan Haule

    Rutgers The State University of New Jersey, Rutgers University, Department of Physics, Rutgers University, Piscataway, New Jersey 08854, USA, Rutgers Univ, Rutgers University, NJ, USA, Department of Physics and Astronomy, Rutgers University