Theory of Insulator Metal Transition and Colossal Magnetoresistance in Doped Manganites

TL;DR

This paper presents a new two-band model with strong correlations and dynamical mean-field theory to explain the insulator-metal transition and colossal magnetoresistance in doped manganites, highlighting phase coexistence.

Contribution

It introduces a novel two-band model incorporating strong correlations and dynamical mean-field theory to quantitatively explain key phenomena in manganites.

Findings

Successfully explains insulator-metal transition

Quantitatively accounts for colossal magnetoresistance

Describes phase coexistence phenomena

Abstract

The persistent proximity of insulating and metallic phases, a puzzling characterestic of manganites, is argued to arise from the self organization of the twofold degenerate e_g orbitals of Mn into localized Jahn-Teller(JT) polaronic levels and broad band states due to the large electron - JT phonon coupling present in them. We describe a new two band model with strong correlations and a dynamical mean-field theory calculation of equilibrium and transport properties. These explain the insulator metal transition and colossal magnetoresistance quantitatively, as well as other consequences of two state coexistence.