TY - JOUR
T1 - Microscopic nature of correlations in multiorbital AFe2As2 (A=K,Rb,Cs)
T2 - Hund's coupling versus Coulomb repulsion
AU - Backes, Steffen
AU - Jeschke, Harald O.
AU - Valentí, Roser
N1 - Publisher Copyright:
© 2015 American Physical Society.
PY - 2015/11/16
Y1 - 2015/11/16
N2 - We investigate via LDA+DMFT (local density approximation combined with dynamical mean field theory) the manifestation of correlation effects in a wide range of binding energies in the hole-doped family of Fe pnictides AFe2As2 (A=K,Rb, Cs) as well as the fictitious FrFe2As2 and a-axis stretched CsFe2As2. This choice of systems allows for a systematic analysis of the interplay of Hund's coupling JH and on-site Coulomb repulsion U in multiorbital Fe pnictides under negative pressure. With increasing ionic size of the alkali metal, we observe a nontrivial change in the iron 3d hoppings, an increase of orbitally-selective correlations, and the presence of incoherent weight at high binding energies that do not show the typical lower Hubbard-band behavior but rather characteristic features of a Hund's metal. This is especially prominent in ab-stretched CsFe2As2. We also find that the coherent/incoherent electronic behavior of the systems is, apart from temperature, strongly dependent on JH, and we provide estimates of the coherence scale T∗. We discuss these results in the framework of reported experimental observations.
AB - We investigate via LDA+DMFT (local density approximation combined with dynamical mean field theory) the manifestation of correlation effects in a wide range of binding energies in the hole-doped family of Fe pnictides AFe2As2 (A=K,Rb, Cs) as well as the fictitious FrFe2As2 and a-axis stretched CsFe2As2. This choice of systems allows for a systematic analysis of the interplay of Hund's coupling JH and on-site Coulomb repulsion U in multiorbital Fe pnictides under negative pressure. With increasing ionic size of the alkali metal, we observe a nontrivial change in the iron 3d hoppings, an increase of orbitally-selective correlations, and the presence of incoherent weight at high binding energies that do not show the typical lower Hubbard-band behavior but rather characteristic features of a Hund's metal. This is especially prominent in ab-stretched CsFe2As2. We also find that the coherent/incoherent electronic behavior of the systems is, apart from temperature, strongly dependent on JH, and we provide estimates of the coherence scale T∗. We discuss these results in the framework of reported experimental observations.
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U2 - 10.1103/PhysRevB.92.195128
DO - 10.1103/PhysRevB.92.195128
M3 - Article
AN - SCOPUS:84952333360
VL - 92
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 1098-0121
IS - 19
M1 - 195128
ER -