Dynamic screening and plasmon spectrum in bilayer graphene

TL;DR

This paper theoretically investigates how external factors like electric bias, temperature, doping, and substrate influence the plasmon spectrum and dielectric properties of bilayer graphene, revealing potential for tunable plasmon modes.

Contribution

It introduces a comprehensive theoretical analysis of the dynamic response and plasmon spectrum in bilayer graphene considering multiple external controls.

Findings

Extra undamped plasmon modes can emerge under electric bias.

These modes have near-zero group velocities and are highly tunable.

External factors significantly affect the dielectric function and plasmon dispersion.

Abstract

We have theoretically studied the collective response properties of the two-dimensional chiral electron gas in bilayer graphene within the random phase approximation. The cooperation of external controlling factors like perpendicular electric bias, temperature, doping, and substrate background provides great freedom to manipulate the dynamic dielectric function and the low-energy plasmon dispersion of the system. Intriguing situations with potential application are systematically explored and discussed. Extra undamped plasmon modes might emerge under electric bias. They have almost zero group velocities and are easy to manipulate.