Role of electric fields on enhanced electron correlation in surface-doped FeSe

Abstract

Electron-doped high-Tc FeSe reportedly has a strong electron correlation that is enhanced with doping. It has been noticed that significant electric fields exist inevitably between FeSe and external donors along with electron transfer. However, the effects of such fields on electron correlation are yet to be explored. Here we study potassium- (K-) dosed FeSe layers using density-functional theory combined with dynamical mean-field theory to investigate the roles of such electric fields on the strength of the electron correlation. We find, very interestingly, the electronic potential-energy difference between the topmost Se and Fe atomic layers, generated by local electric fields of ionized K atoms, weakens the Se-mediated hopping between Fe d orbitals. Since it is the dominant hopping channel in FeSe, its reduction narrows the Fe d bands near the Fermi level, enhancing the electron correlation. This effect is orbital dependent and occurs in the topmost FeSe layer only. We also find the K dosing may increase the Se height, enhancing the electron correlation further. These results shed new light on the comprehensive study of high-Tc FeSe and other low-dimensional systems.

9 pages including Supplemental Material. 5 figures in the main text and 4 figures in Supplemental Material

References in corpus (10)

• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Strong electronic correlations from Hund's coupling
• Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
• Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base
• Origins of anomalous electronic structures of epitaxial graphene on silicon carbide
• Monolayer FeSe on SrTiO${}_3$
• Electronic Structure and Superconductivity of FeSe-Related Superconductors
• Origin of charge transfer and enhanced electron-phonon coupling in single unit-cell FeSe films on SrTiO3
• Unfolding the band structure of disordered solids: from bound states to high-mobility Kane fermions
• High-temperature superconductivity in one-unit-cell FeSe films

Cited by in corpus (2)

• Modulation doping of the FeSe monolayer on SrTiO${}_3$
• Causal optimization method for imaginary-time Green's functions in interacting electron systems