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arXiv · 1503.06467

DMFT+NRG study of spin-orbital separation in a three-band Hund's metal

K. M. Stadler·A. Weichselbaum·Z. P. Yin·J. von Delft·G. Kotliar
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Abstract

We show that the numerical renormalization group (NRG) is a viable multi-band impurity solver for Dynamical Mean Field Theory (DMFT), offering unprecedent real-frequency spectral resolution at arbitrarily low energies and temperatures. We use it to obtain a numerically exact DMFT solution to the Hund's metal problem for a three-orbital model with filling factor $n_d=2$. The ground state is a Fermi liquid. The one-particle spectral function has a strong particle-hole asymmetry, with a clear apparent power law for positive frequencies only. With increasing temperature it shows a coherence-incoherence crossover with spectral weight transfered from low to high energies and evolves qualitatively differently from a doped Mott insulator. The spin and orbital spectral functions show "spin-orbital separation": spin screening occurs at much lower energies than orbital screening. The renormalization group flows clearly reveal the relevant physics at all energy scales.

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K. M. Stadler, A. Weichselbaum, Z. P. Yin, J. von Delft, G. Kotliar. 2015-03-22. DMFT+NRG study of spin-orbital separation in a three-band Hund's metal. https://doi.org/10.1103/physrevlett.115.136401

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