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arXiv 1211.2015cond-mat.mtrl-scicond-mat.str-elcond-mat.supr-con
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Hund金属的轨道选择性:铁硫族化合物

Orbital Selectivity in Hund's metals: The Iron Chalcogenides

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

摘要:

我们发现,电子关联导致一个坏的金属状态的硫属化物FeSe和FeTe,尽管中间值的哈伯德排斥$U$和Hund的规则耦合$J$。准粒子重量$Z$作为相互作用项的函数的演化揭示了在$U \simeq$ 2.5 eV处的明显交叉。在弱耦合极限下,$Z$随$d$的变化而减小,超过交叉耦合后,它们对$U$的依赖性变弱,而对$J$的依赖性变强。即使通常轨道选择性莫特跃迁只发生在相对较大的$U$值时,也会出现$Z$的显著轨道依赖性。由于Hubbard $U$和Hund的$J$的联合作用,准粒子相干性的这种两阶段减少表明铁基超导体可以被称为Hund的相关金属。

英文摘要:

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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