Exchange effect and magneto-plasmon mode dispersion in an anisotropic two-dimensional electronic system

TL;DR

This paper theoretically investigates how exchange interactions and magneto-plasmon mode dispersions behave in an anisotropic two-dimensional electronic system under a perpendicular magnetic field, highlighting the effects of anisotropy.

Contribution

It introduces a model for anisotropic 2D systems, analyzing exchange effects and magneto-plasmon dispersion with a self-consistent approach, relevant for materials like monolayer phosphorus.

Findings

Exchange effect is weaker in anisotropic systems compared to isotropic ones.

Magneto-plasmon dispersion depends on the wave vector direction.

Anisotropy influences the collective excitation modes.

Abstract

The exchange effect and the magneto-plasmon mode dispersion are studied theoretically for an anisotropic two-dimensional electronic system in the presence of an uniform perpendicular magnetic field. Employing an effective low-energy model with anisotropic effective masses, which is relevant for a monolayer of phosphorus, the exchange effect due to the electron-electron interaction is treated within the self-consistent Hartree-Fock approximation. The magneto-plasmon mode dispersion is obtained by solving a Bethe-Salpeter equation for the electron density-density correlation function within the ladder diagram approximation. It is found that the exchange effect is reduced in the anisotropic system in comparison with the isotropic one. The magneto-plasmon mode dispersion shows a clear dependence on the direction of the wave vector.