# Nature of the Doping-Driven Metal-Insulator Transition in Correlated Electron Systems with strong Hund's Exchange Coupling

## TL;DR

This paper investigates how doping induces a metal-insulator transition in multi-orbital Hubbard models with Hund's coupling, revealing a first-order transition with a broad metallic phase and distinct local moment behavior.

## Contribution

It demonstrates that Hund's coupling significantly alters the transition, creating a connected metallic phase and unique magnetic properties not seen in single-orbital models.

## Key findings

- First-order transition with coexistence region.
- Insulating phase linked to a broad metallic phase.
- Frozen local moments appear only on the insulating side.

## Abstract

We study the doping-driven Mott metal-insulator transition for multi-orbital Hubbard models with Hund's exchange coupling at finite temperatures. As in the single-orbital Hubbard model, the transition is of first-order within dynamical mean field theory, with a coexistence region where two solutions can be stabilized. We find, that in the presence of finite Hund's coupling, the insulating phase is connected to a badly metallic phase, which extends to surprisingly large dopings. While fractional power-law behavior of the self-energies on the Matsubara axis is found on both sides of the transition, a regime with frozen local moments develops only on the branch connected to the insulating phase.