Correlation effects in the tetragonal and collapsed tetragonal phase of CaFe2As2

TL;DR

This study uses advanced computational methods to analyze how electronic correlations affect the electronic structure of CaFe2As2 in different phases, revealing phase-dependent orbital mass renormalizations consistent with experimental data.

Contribution

It provides a detailed DFT+DMFT analysis of correlation effects in CaFe2As2, highlighting phase-dependent orbital mass renormalizations and hybridization changes.

Findings

Orbital-dependent mass renormalizations match ARPES data.

Fermi surface topology remains largely unaffected by correlations.

Increased hybridization in the collapsed tetragonal phase.

Abstract

We investigate the role of correlations in the tetragonal and collapsed tetragonal phases of CaFe2As2 by performing charge self-consistent DFT+DMFT (density functional theory combined with dynamical mean-field theory) calculations. While the topology of the Fermi surface is basically unaffected by the inclusion of correlation effects, we find important orbital-dependent mass renormalizations which show good agreement with recent angle-resolved photoemission (ARPES) experiments. Moreover, we observe a markedly different behavior of these quantities between the low-pressure tetragonal and the high-pressure collapsed tetragonal phase. We attribute these effects to the increased hybridization between the iron- and arsenic orbitals as one enters the collapsed tetragonal phase.