Magnetic Field Effect in One-Dimensional Charge Ordering Systems

TL;DR

This study investigates how an external magnetic field influences charge ordering in a one-dimensional extended Hubbard model, revealing enhanced charge correlations and increased transition temperatures, with implications for magnetoresistance in molecular conductors.

Contribution

It demonstrates the magnetic field's role in enhancing charge order and transition temperature in a one-dimensional model, connecting theoretical results to experimental observations.

Findings

Magnetic field enhances charge order correlation near critical regime.

Zeeman coupling promotes transition to fully spin-polarized state.

Charge-ordering transition temperature increases with magnetic field.

Abstract

We study effects of an external magnetic field on charge ordering in the one-dimensional extended Hubbard model at quarter filling by means of the quantum Monte Carlo method. We find that the Zeeman coupling enhances the charge order correlation, which is prominent when the system is located in the critical regime near the charge ordering transition at zero magnetic field. This behavior is interpreted in terms of the crossover to the fully spin-polarized limit where the model is exactly solvable. Furthermore, by incorporating the interchain Coulomb repulsion, we show that the charge-ordering transition temperature is raised by the magnetic field. We also discuss the relevance of our results to magnetoresistance effects observed in molecular conductors.