Screened topological plasmons in graphene plasmonic crystals

TL;DR

This paper investigates topological properties of screened plasmons in a periodically modulated graphene sheet on a metallic substrate, revealing nontrivial topological bands and edge states through a developed quantization theory.

Contribution

It introduces a theoretical framework for quantizing screened plasmons in graphene plasmonic crystals and analyzes their topological band structure and edge states.

Findings

The crystal supports nontrivial topological bands with quantized geometric phase.

Edge states appear within the band gap and undergo topological phase transitions.

The framework extends the study of topology in layered media and external modulation.

Abstract

We study topological effects in an one-dimensional plasmonic crystal formed by the screened plasmons emerging in a periodically modulated graphene sheet, placed on top of a metallic substrate. To this end, we develop the theory of quantization of screened plasmons, as appropriate for lossless graphene described by a Drude conductivity. By analyzing the resulting band structure, we show that the crystal sustains nontrivial topological bands, with quantized geometric phase. We further show that in a finite, open system, edge states appear within the band gap, which undergo a topological phase transition and merge with bulk states as the modulation increases. Our work provides a robust theoretical framework for the study of band structure and topology of layered media, and extends the possibilities for engineering two-dimensional materials with external modulation.