Temperature dependence of the resistivity in the double-exchange model

TL;DR

This study investigates how resistivity varies with temperature in the double exchange model, highlighting the roles of electronic and spin correlations around the ferromagnetic transition.

Contribution

It introduces a Schwinger boson approach combined with memory function formalism to analyze temperature-dependent resistivity in the double exchange model.

Findings

Resistivity increases monotonically in the ferromagnetic state with temperature.

Resistivity in the paramagnetic state remains nearly constant due to short-range correlations.

Electronic state variations significantly influence resistivity across phases.

Abstract

The resistivity around the ferromagnetic transition temperature in the double exchange model is studied by the Schwinger boson approach. The spatial spin correlation responsible for scattering of conduction electrons are taken into account by adopting the memory function formalism. Although the correlation shows a peak lower than the transition temperature, the resistivity in the ferromagnetic state monotonically increases with increasing temperature due to a variation of the electronic state of the conduction electron. In the paramagnetic state, the resistivity is dominated by the short range correlation of scattering and is almost independent of the temperature. It is attributed to a cancellation between the nearest-neighbor spin correlation, the fermion bandwidth, and the fermion kinetic energy. This result implies the importance of the temperature dependence of the electronic states of the conduction electron as well as the localized spin states in both ferromagnetic and paramagnetic phases.