Integrated Plasmonics: Broadband Dirac Plasmons in Borophene

TL;DR

This paper explores borophene, a 2D metal, revealing its unique broadband plasmon modes with low damping, driven by anisotropic Dirac cones, promising advancements in optoelectronic applications.

Contribution

It uncovers the broadband Dirac plasmons in borophene and links their properties to anisotropic electronic structures, advancing understanding of 2D metallic plasmonics.

Findings

Discovery of two major plasmon modes with low damping in borophene.

Identification of anisotropic 1D plasmons from tilted Dirac cones.

Potential for directional polariton transport and broadband optical communication.

Abstract

The past decade has witnessed numerous discoveries of two-dimensional (2D) semimetals and insulators, whereas 2D metals are rarely identified. Borophene, a monolayer boron sheet, has recently emerged as a perfect 2D metal with unique structure and electronic properties. Here we study collective excitations in borophene, which exhibit two major plasmon modes with low damping rates extending from infrared to ultraviolet regime. The anisotropic 1D plasmon originates from electronic excitations of tilted Dirac cones in borophene, analogous to that in heavily doped Dirac semimetals. These features make borophene promising to realize directional polariton transportation and broadband optical communications for next-generation optoelectronic devices.