# Orbital-selective Mott phase in multiorbital models for iron pnictides and chalcogenides

## TL;DR

This paper investigates the orbital-selective Mott phase in multiorbital models for iron-based superconductors, emphasizing the role of intersite spin correlations and hybridization in stabilizing this phase.

## Contribution

The study develops a Landau free-energy functional and highlights the importance of intersite spin correlations in the orbital-selective Mott transition, providing new insights beyond previous models.

## Key findings

- Orbital-selective Mott phase is robust in multiorbital models for iron pnictides and chalcogenides.
- Intersite spin correlations are crucial for the renormalization of hybridization.
- The hybridization amplitude approaches zero, enabling the orbital-selective Mott transition.

## Abstract

There is increasing recognition that the multiorbital nature of the 3d electrons is important to the proper description of the electronic states in the normal state of the iron-based superconductors. Earlier studies of the pertinent multiorbital Hubbard models identified an orbital-selective Mott phase, which anchors the orbital-selective behavior seen in the overall phase diagram. An important characteristics of the models is that the orbitals are kinetically coupled -- i.e. hybridized -- to each other, which makes the orbital-selective Mott phase especially nontrivial. A U(1) slave-spin method was used to analyze the model with nonzero orbital-level splittings. Here we develop a Landau free-energy functional to shed further light on this issue. We put the microscopic analysis from the U(1) slave-spin approach in this perspective, and show that the intersite spin correlations are crucial to the renormalization of the bare hybridization amplitude towards zero and the concomitant realization of the orbital-selective Mott transition. Based on this insight, we discuss additional ways to study the orbital-selective Mott physics from a dynamical competition between the interorbital hybridization and collective spin correlations. Our results demonstrate the robustness of the orbital-selective Mott phase in the multiorbital models appropriate for the iron-based superconductors.