Band magnetism with inter-site correlations and interactions

TL;DR

This paper develops a Hamiltonian model for narrow band electrons to better understand ferromagnetism, showing that inter-site interactions significantly influence Curie temperatures and align theoretical predictions with experimental data.

Contribution

It introduces a Hamiltonian incorporating inter-site correlations and interactions, providing a more accurate description of ferromagnetism in narrow band systems.

Findings

Inter-site interactions decrease magnetic moments with temperature.

Calculated Curie temperatures align with experimental values.

On-site interaction alone overestimates Curie temperatures.

Abstract

We introduce the Hamiltonian to describe narrow band electrons. The physics of driving forces towards ferromagnetism is re-examined. Using different approximations it has been shown that the magnetic moments created by inter-site interaction and inter-site kinetic correlation decrease quickly with temperature. As a result of these interactions and the realistic density of states (DOS) the Curie temperatures calculated after fitting magnetic moments to their low temperature values are realistic. In the past the Curie temperatures calculated using only the on-site interaction were much higher than the experimental temperatures.