Validity of the Local Approximation in Iron- Pnictides and Chalcogenides

TL;DR

This paper demonstrates that single-site DMFT effectively describes the normal state of iron pnictides and chalcogenides due to the local nature of the self-energy in moderate mass renormalization regimes, validated through CTQMC solutions.

Contribution

The study introduces a cluster DMFT approach and confirms the validity of single-site DMFT for Hund's metals in certain regimes, supported by CTQMC calculations.

Findings

Self-energy is very local in moderate mass renormalizations.

Single-site DMFT is justified for these materials.

Minus sign problem is manageable with CTQMC.

Abstract

We introduce a cluster DMFT (Dynamical Mean Field Theory) approach to study the normal state of the iron pnictides and chalcogenides. In the regime of moderate mass renormalizations, the self-energy is very local, justifying the success of single site DMFT for these materials and for other Hunds metals. We solve the corresponding impurity model with CTQMC (Continuous Time Quantum Monte-Carlo) and find that the minus sign problem is not severe in regimes of moderate mass renormalization.