Plasma Excitations in Graphene: Their Spectral Intensity and Temperature Dependence in Magnetic Field

TL;DR

This study investigates how magnetic fields and temperature influence plasma excitations in graphene, providing detailed spectral and dispersion insights using theoretical models and suggesting experimental verification methods.

Contribution

It offers a comprehensive theoretical analysis of plasma excitations in graphene under magnetic fields and temperature variations, including dispersion relations and damping mechanisms.

Findings

Critical wave vector depends on magnetic field and transition levels

Finite temperature induces plasma resonances via Fermi distribution

Spectroscopic methods can verify magnetic and thermal effects

Abstract

In this paper, we calculated the dielectric function, the loss function, the magnetoplasmon dispersion relation and the temperature-induced transitions for graphene in a uniform perpendicular magnetic field B. The calculations were performed using the Peierls tight-binding model to obtain the energy band structure and the random-phase approximation to determine the collective plasma excitation spectrum. The single-particle and collective excitations have been precisely identified based on the resonant peaks in the loss function. The critical wave vector at which plasmon damping takes place is clearly established. This critical wave vector depends on the magnetic field strength as well as the levels between which the transition takes place. The temperature effects were also investigated. At finite temperature, there are plasma resonances induced by the Fermi distribution function. Whether such plasmons exist is mainly determined by the field strength, temperature, and momentum. The inelastic light scattering spectroscopies could be used to verify the magnetic field and temperature induced plasmons.