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arXiv · 1211.2015

Orbital Selectivity in Hund's metals: The Iron Chalcogenides

N. Lanatà·H. U. R. Strand·G. Giovannetti·B. Hellsing·L. de' Medici·M. Capone
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Abstract

We show that electron correlations lead to a bad metallic state in chalcogenides FeSe and FeTe despite the intermediate value of the Hubbard repulsion $U$ and Hund's rule coupling $J$. The evolution of the quasi particle weight $Z$ as a function of the interaction terms reveals a clear crossover at $U \simeq$ 2.5 eV. In the weak coupling limit $Z$ decreases for all correlated $d$ orbitals as a function of $U$ and beyond the crossover coupling they become weakly dependent on $U$ while strongly depend on $J$. A marked orbital dependence of the $Z$'s emerges even if in general the orbital-selective Mott transition only occurs for relatively large values of $U$. This two-stage reduction of the quasi particle coherence due to the combined effect of Hubbard $U$ and the Hund's $J$, suggests that the iron-based superconductors can be referred to as Hund's correlated metals.

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N. Lanatà, H. U. R. Strand, G. Giovannetti, B. Hellsing, L. de' Medici, M. Capone. 2012-11-08. Orbital Selectivity in Hund's metals: The Iron Chalcogenides. https://doi.org/10.1103/physrevb.87.045122

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