Electron correlation induced small anisotropy in iron-based superconductors

TL;DR

This study uses advanced theoretical methods to show that electron correlations significantly reduce electrical anisotropy in iron-based superconductors, explaining their observed isotropic transport properties.

Contribution

It demonstrates that considering electron correlations via DMFT is crucial for accurately describing anisotropic transport in iron-based superconductors, a step beyond conventional DFT.

Findings

Electron correlation suppresses bandwidth near the Fermi level.

DMFT predicts reduced electrical anisotropy compared to DFT.

Correlation effects explain small anisotropic resistivity in experiments.

Abstract

We have investigated the electron correlation effect on the electronic structures and transport properties of the iron-based superconductors using the density functional theory (DFT) and dynamical mean field theory (DMFT). By considering the Fe 3d electron correlation using the DMFT, the bandwidth near the Fermi level is substantially suppressed compared to the conventional DFT calculation. Because of the different renormalization factors of each 3d orbital, the DMFT gives considerably reduced electrical anisotropy compared to the DFT results, which explains the unusually small anisotropic resistivity and superconducting property observed in the iron-based superconductors. We suggest that the electron correlation effect should be considered to explain the anisotropic transport properties of the general d/f valence electron system.