Ground State of the Double Exchange Model

TL;DR

This paper studies the ground-state properties of the double exchange model in manganites, revealing how magnetic fields, doping, and electronic correlations influence magnetic phases and phase separation.

Contribution

It introduces a semiclassical and slave-boson approach to analyze electronic correlations and their effects on magnetic properties in manganites.

Findings

Magnetic field affects the canted angle similarly to doping.

Weak dependence of canted angle on Coulomb interaction.

Phase separation may occur at low doping levels.

Abstract

We invesitgate the electronic correlation effect on the ground-state properties of the double exchange model for manganites by using a semiclassical approach and the slave-boson technique. It is shown that magnetic feild has a similar effect on the canted angle between manganese spins as doping concentration does, and the canted angle exhibits weak dependence on the Coulomb interaction. We have shown that the phase separation may take place at low doping. In the slave-boson saddle-point approximation in the ferromagnetic metallic regime, the dependence of the magnetization and the Curie temperature on the doping concentration exhibits maxima near 1/3 doping. These results agree with experimental data and suggest that the electronic correlation plays an important role for understanding the ground-state properties of manganites.