Interband Plasmonics with p-block Elements

TL;DR

This paper explores how interband transitions in p-block elements like Bi, Sb, and Ga can produce plasmonic effects in the near-ultraviolet visible range, offering alternatives to noble metal-based plasmonics.

Contribution

It demonstrates that interband transitions, rather than Drude carriers, can induce localized surface plasmon-like resonances in these materials, opening new avenues for tunable plasmonic nanostructures.

Findings

Interband transitions dominate the dielectric response in Bi, Sb, and Ga.

Localized surface plasmon-like resonances are induced by interband transitions.

Plasmonic effects can be tuned via band structure and electronic state occupancy.

Abstract

We investigate the origin of the near-ultraviolet visible plasmonic properties of three elemental materials from the p-block: Bi, Sb and Ga, with the aim to achieve and exploit unconventional plasmonic effects beyond those provided by noble metals. At such aim, we review and analyze a broad range of optically-determined dielectric functions e of these elemental materials available in the literature, covering a wide photon energy range (from 0.03 to 24 eV). It is shown that the contribution of Drude-like carriers to e1 (real part of e) in the near-ultraviolet visible is negligible for Bi and Sb and moderate for Ga. In contrast, the interband transitions of these elemental materials show a high oscillator strength that yields a strong negative contribution to e1 in the near-ultraviolet visible. Therefore in these materials interband transitions are not a mere damping channel detrimental to plasmonic properties. Remarkably, these interband transitions induce fully (partially) the localized surface plasmon-like resonances taking place in Bi and Sb (Ga) nanostructures in the near-ultraviolet visible. Plasmonic properties achieved through interband transitions, without Drude-like carrier excitation, are very attractive phenomena because they may give rise to a rich and broad class of nanostructures and metamaterials in which plasmonic effects will be tunable through the tailoring of band structure and by the occupancy of electronic states.