Competing phases in a model of Pr-based cobaltites

TL;DR

This paper investigates how an external magnetic field influences competing phases in a hole-doped two-band Hubbard model relevant to Pr-based cobaltites, revealing a suppression of excitonic condensation and a transition to magnetic order with significant electron density changes.

Contribution

It provides the first dynamical mean-field theory analysis of magnetic field effects on excitonic and ferromagnetic phases in Pr-based cobaltite models.

Findings

Magnetic field suppresses excitonic condensate.

Magnetic order emerges with electron density change.

Pr$^{3+}$ abundance predicted to increase at high fields.

Abstract

Motivated by the physics of Pr-based cobaltites, we study the effect of the external magnetic field in the hole-doped two-band Hubbard model close to instabilities toward the excitonic condensation and ferromagnetic ordering. Using the dynamical mean-field theory we observe a field-driven suppression of the excitonic condensate. The onset of a magnetically ordered phase at the fixed chemical potential is accompanied by a sizable change of the electron density. This leads us to predict that Pr$^{3+}$ abundance increases on the high-field side of the transition.