Double Exchange Model in Triangular Lattice Studied by Truncated Polynomial Expansion Method

TL;DR

This paper investigates the low-temperature magnetic phases of the double exchange model on a triangular lattice using the truncated polynomial expansion method, revealing complex phase transitions influenced by lattice frustration and superexchange interactions.

Contribution

It introduces the application of the truncated polynomial expansion method to study the double exchange model on a triangular lattice, enabling efficient analysis of magnetic phases.

Findings

A stable 120-degree spin configuration at half-filling due to frustration.

A transition from ferromagnetic to flux phase at quarter-filling influenced by superexchange.

Method reduces computational complexity and allows parallel computation.

Abstract

The low temperature properties of double exchange model in triangular lattice are investigated via truncated polynomial expansion method (TPEM), which reduces the computational complexity and enables parallel computation. We found that for the half-filling case a stable 120-degree spin configuration phase occurs owing to the frustration of triangular lattice and is further stabilized by antiferromagnetic (AF) superexchange interaction, while a transition between a stable ferromagnetic (FM) phase and a unique flux phase with small finite-size effect is induced by AF superexchange interaction for the quarter-filling case.