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

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