Quality of mid-IR plasmon resonances in highly mismatched alloys

Plasmonic applications in the mid-IR range primarily rely on doped semiconductors. The plasmonic properties of highly mismatched alloys (HMAs) – modified semiconductors with an alloying element that has highly different electronegativity from the host semiconductor elements – have not been explored. We study the bulk plasmon resonances of a large class of HMAs and show that they have plasmon resonances in the THz to mid-IR range. We compare their resonance quality with leading mid-IR plasmonic materials using a figure of merit that describes the potential of a material to scatter or absorb light. We show that HMAs can be competitive with many doped semiconductor systems.