Gate-tunable infrared plasmons in electron-doped single-layer antimony

TL;DR

This theoretical study predicts tunable mid-infrared plasmons in electron-doped single-layer antimony, driven by spin-orbit coupling and external bias, with potential applications in plasmonic and optoelectronic devices.

Contribution

It introduces a model showing how spin-orbit effects and bias enable tunable plasmon excitations in antimonene, a novel 2D semiconductor.

Findings

Plasmons in antimonene can be tuned via doping and bias.

Plasmons exhibit low losses and negative dispersion.

Spin-splitting induces interband resonances affecting collective excitations.

Abstract

We report on a theoretical study of collective electronic excitations in single-layer antimony crystals (antimonene), a novel two-dimensional semiconductor with strong spin-orbit coupling. Based on a tight-binding model, we consider electron-doped antimonene and demonstrate that the combination of spin-orbit effects with external bias gives rise to peculiar plasmon excitations in the mid-infrared spectral range. These excitations are characterized by low losses and negative dispersion at frequencies effectively tunable by doping and bias voltage. The observed behavior is attributed to the spin-splitting of the conduction band, which induces interband resonances, affecting the collective excitations. Our findings open up the possibility to develop plasmonic and optoelectronic devices with high tunability, operating in a technologically relevant spectral range.