Magnetic transitions in a Double Exchange-Holstein model with e-ph interactions coupled to magnetism

TL;DR

This paper investigates the magnetic phase transitions in a Double Exchange-Holstein model with electron-phonon interactions coupled to magnetism, revealing discontinuous transitions and resistivity peaks similar to manganite behavior.

Contribution

It introduces a combined mean-field and Lang-Firsov approach to analyze how electron-phonon coupling influences magnetic transitions in the DE-H model.

Findings

Discontinuous magnetic transitions occur with strong dependence of g on m.

Resistivity peaks near critical temperature are observed over broad parameter ranges.

The model reproduces experimental features seen in manganites.

Abstract

In this work we study the Double Exchange-Holstein (DE-H) model with an electron-phonon interaction $\gamma$ coupled to magnetism. The analysis is performed combining a mean-field approximation for the double exchange interaction and the Lang-Firsov transformation for the electron-phonon interaction. Discontinuous magnetic transitions appear when the dependence of $g$ with $m$ is sufficiently large, resembling those experimentally observed in manganites. We observe that the characteristic resistivity peak that arises near the critical temperature appears for broad ranges of the system parameter values, unlike what occurs in a constant--$\gamma$ model.