Non-Degenerate Ground State in the Antiferromagnetic Double-Exchange Model on a Triangular Lattice

TL;DR

This paper investigates the ground states of an itinerant electron system with frustration on a triangular lattice, revealing how long-range double exchange interactions lift degeneracy and influence spin ordering.

Contribution

It introduces a study of the antiferromagnetic double-exchange model on a triangular lattice, showing degeneracy lifting due to long-range interactions and analyzing resulting spin orderings.

Findings

Degeneracy in the model is lifted by long-range double exchange interactions.

Ground state exhibits specific spin ordering patterns.

Long-range interactions influence the macroscopic properties of the system.

Abstract

In order to study effects of frustration in an itinerant electron system, we investigate ground states of the antiferromagnetic double-exchange model on a triangular lattice. In this model, pseudo-spins are coupled to electron transfer integrals in such a way that antiparallel configurations of pseudo-spins gain kinetic energies. Although the antiferromagnetic Ising model on a triangular lattice shows macroscopic dengenerate ground states, the present model shows that the degeneracy is lifted due to long-range natures of the double exchange interactions. Spin ordering at the ground state is also discussed.