Fig. 1: Overview figure.
Left panel: A schematic illustration of “site-differentiated Hund metal” physics in Fe3GeTe2. Colored areas highlight different regimes or phases; Mott insulator (dark green; i.e., whose charge gap is opened due to Hubbard U), Mott metal (light green; i.e., whose correlated metallic behavior is governed by U), weakly correlated metal (yellow; electronic correlation is weak enough), and Hund metal (red; i.e., whose correlated metallic behavior is governed by Hund JH). For more details to define each region of the phase diagram, we refer to refs. 35,42,61. While both Fe sites fall into the Hund metal regime, they are clearly differentiated in terms of electron scattering rate Γ, quasiparticle effective mass m*/mb, and Sommerfeld coefficient γ (as depicted along z axis) which are attributed to the electronic structure details (see the schematic DOS). In parentheses shown are the calculated spin-orbital-averaged values of (Γ, m*/mb, γ) taken at T = 100 K. The unit of Γ is meV. The x- and y axis corresponds to JH/U and U/W, respectively. U = 5.0 and J = 0.9 eV (JH/U = 0.18) were used for both Fe-I and Fe-II; see “Methods” for a more detailed discussion. The effective bandwidth WFe-I for Fe-I is found to be smaller than that of Fe-II through the analysis of the hybridization function (see the main text). A rough estimation of their difference based on the integrated DOS yields ~1.6 eV (see the main text). Right panel: Crystal structure of Fe3GeTe2.
