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arXiv · 1906.11853

Effect of non-local correlations on the electronic structure of LiFeAs

Karim Zantout·Steffen Backes·Roser Valentí
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Abstract

We investigate the role of non-local correlations in LiFeAs by exploring an ab-initio-derived multi-orbital Hubbard model for LiFeAs via the Two-Particle Self-Consistent (TPSC) approach. The multi-orbital formulation of TPSC approximates the irreducible interaction vertex to be an orbital-dependent constant, which is self-consistently determined from local spin and charge sum rules. Within this approach, we disentangle the contribution of local and non-local correlations in LiFeAs and show that in the local approximation one recovers the dynamical-mean field theory (DMFT) result. The comparison of our theoretical results to most recent angular-resolved photoemission spectroscopy (ARPES) and de-Haas van Alphen (dHvA) data shows that non-local correlations in LiFeAs are decisive to describe the measured spectral function $A(\vec k,ω)$, Fermi surface and scattering rates. These findings underline the importance of non-local correlations and benchmark different theoretical approaches for iron-based superconductors.

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Karim Zantout, Steffen Backes, Roser Valentí. 2020-10-23. Effect of non-local correlations on the electronic structure of LiFeAs. https://doi.org/10.1103/physrevlett.123.256401

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