Coulomb correlations in a germanide iron-based superconductor: The example of YFe2Ge2

S. L. Skornyakov; V. I. Anisimov

doi:10.1103/PhysRevB.107.235103

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Coulomb correlations in a germanide iron-based superconductor: The example of YFe2Ge2

S. L. Skornyakov, V. I. Anisimov

DOI 10.1103/PhysRevB.107.235103 · Physical Review B

T1

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Abstract

We report results of a detailed theoretical study of the effect of Coulomb correlations on the structural, electronic, and magnetic properties of the non-pnictide iron-based superconductor YFe2Ge2. In particular, by employing the density functional theory plus dynamical mean-field theory method (DFT+DMFT) we perform a structural optimization of the unit-cell volume and the internal coordinate zGe of Ge. Our results for the lattice parameters obtained by DFT+DMFT show a much better agreement with experiment as compared to those calculated by DFT implying the importance of correlation effects. We show that YFe2Ge2 is a moderately correlated system with electron-electron correlations being strong enough to renormalize the low-energy band structure but not sufficient to form Hubbard bands, in close analogy to the iron-based pnictides and chalcogenides. The analysis of the local spin-spin correlation function and momentum-dependent spin susceptibility χ(q) indicates the correlation induced formation of short-lived local moments in the Fe t2g states and the presence of competing spin fluctuations, in agreement with experiment.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YFe2Ge2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.4	Pressure not reported	unknown
YFe2Ge2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1.8	Pressure not reported	unknown