Examining the performance of refractory conductive ceramics as plasmonic materials: a theoretical approach

TL;DR

This study uses first-principles calculations to evaluate refractory ceramics as potential plasmonic materials, identifying nitrides like TiN, ZrN, and HfN as promising alternatives to noble metals for optical applications.

Contribution

It provides a comprehensive theoretical analysis of electronic and optical properties of refractory ceramics, highlighting their suitability for plasmonic applications compared to traditional metals.

Findings

Transition metal nitrides exhibit plasmonic performance comparable to noble metals.

Carbides show high losses, making them unsuitable for plasmonics.

TiN and TaC are optimal for broad-spectrum photothermal energy conversion.

Abstract

The main aim of this study is to scrutinize promising plasmonic materials by understanding their electronic structure and correlating them to the optical properties of selected refractory materials. For this purpose, the electronic and optical properties of the conductive ceramics TiC, ZrC, HfC, TaC, WC, TiN, ZrN, HfN, TaN, and WN are studied systematically by means of first-principles density functional theory. A full ab initio procedure to calculate plasma frequency from the electronic band structure is discussed. The dielectric functions are calculated by including electronic interband and intraband transitions. Our calculations confirm that transition metal nitrides, such as TiN, ZrN, and HfN, are the strongest candidates, exhibiting performance comparable to that of conventional noble metals in the visible to the near-infrared regions. On the other hand, carbides are not suitable for plasmonic applications because they show very large losses in the same regions. From our calculated dielectric functions, the scattering and absorption efficiencies of nanoparticles made of these refractory materials are evaluated. It is revealed that TiN and TaC are the best candidate materials for applications in photothermal energy conversion over a broad spectral region. Furthermore, quality factors for localized surface plasmon resonance and surface plasmon polaritons are calculated to compare quantitative performances, and ZrN and HfN are found to be comparable to conventional plasmonic metals such as silver and gold