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arXiv · 0911.1940

Fermi-liquid, non-Fermi-liquid, and Mott phases in iron pnictides and cuprates

Hiroshi Ishida·Ansgar Liebsch
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Abstract

The role of Coulomb correlations in the iron pnictide LaFeAsO is studied by generalizing exact diagonalization dynamical mean field theory to five orbitals. For rotationally invariant Hund's rule coupling a continuous transition from a paramagnetic Fermi-liquid phase to a non-Fermi-liquid metallic phase exhibiting frozen moments is found at moderate Coulomb energies. For Ising-like exchange, this transition is first order and occurs at a lower critical Coulomb energy. The correlation-induced scattering rate as a function of doping relative to half-filling, i.e., delta = n/5-1, where n=6 for the undoped material, is shown to be qualitatively similar to the one in the two-dimensional single-band Hubbard model. In this scenario, the parent Mott insulator of LaFeAsO is the half-filled n=5 limit, while the undoped n=6 material corresponds to the critical doping region delta_c ~ 0.2 in the cuprates, on the verge between the Fermi-liquid phase of the overdoped region and the non-Fermi-liquid pseudogap phase in the underdoped region.

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Hiroshi Ishida, Ansgar Liebsch. 2010-03-06. Fermi-liquid, non-Fermi-liquid, and Mott phases in iron pnictides and cuprates. https://doi.org/10.1103/physrevb.81.054513

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