Comparative study of the electronic and magnetic properties of BaFe(2)As(2) and BaMn(2)As(2) using the Gutzwiller approximation

TitleComparative study of the electronic and magnetic properties of BaFe(2)As(2) and BaMn(2)As(2) using the Gutzwiller approximation
Publication TypeJournal Article
Year of Publication2011
AuthorsYao YX, Schmalian J, Wang CZ, Ho KM, Kotliar G
Journal TitlePhysical Review B
Volume84
Pages245112
Date Published12
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000298115800005
Keywordschalcogenides, iron pnictides, spectra, superconductivity, systems, transition
Abstract

To elucidate the role played by the transition-metal ion in the pnictide materials, we compare the electronic and magnetic properties of BaFe(2)As(2) with BaMn(2)As(2). To this end we employ the LDA + Gutzwiller method to analyze the mass renormalizations and the size of the ordered magnetic moment of the two systems. We study a model that contains all five transition-metal 3d orbitals together with the Ba 5d and As 4p states (ddp-model) and compare these results with a downfolded model that consists of Fe/Mn d states only (d-model). Electronic correlations are treated using the multiband Gutzwiller approximation. The paramagnetic phase has also been investigated using the LDA + Gutzwiller method with electron density self-consistency. The renormalization factors for the correlated Mn 3d orbitals in the paramagnetic phase of BaMn(2)As(2) are shown to be generally smaller than those of BaFe(2)As(2), which indicates that BaMn(2)As(2) has stronger electron correlation effect than BaFe(2)As(2). The screening effect of the main As 4p electrons to the correlated Fe/Mn 3d electrons is evident by the systematic shift of the results to the larger Hund's rule coupling J side from the ddp-model compared with those from the d-model. A gradual transition from paramagnetic state to the antiferromagnetic ground state with increasing J is obtained for the models of BaFe(2)As(2) which has a small experimental magnetic moment, while a rather sharp jump occurs for the models of BaMn(2)As(2), which has a large experimental magnetic moment. The key difference between the two systems is shown to be the d-level occupation. BaMn(2)As(2), with approximately five d electrons per Mn atom, is for the same values of the electron correlations closer to the transition to a Mott insulating state than BaFe(2)As(2). Here an orbitally selective Mott transition, required for a system with close to six electrons, only occurs at significantly larger values for the Coulomb interactions.

URL<Go to ISI>://WOS:000298115800005
DOI10.1103/PhysRevB.84.245112
Alternate JournalPhys. Rev. B