Lossless plasmons in highly mismatched alloys

TL;DR

This paper investigates how highly mismatched alloys can host lossless plasmons by exploiting band splitting and doping, identifying conditions for lossless plasmonic behavior with potential for practical applications.

Contribution

It introduces the concept of lossless plasmons in HMAs with conduction band anticrossing and maps the parameter space for their realization.

Findings

Lossless plasmon frequency windows exist in HMAs due to band splitting.

Heavy effective mass HMAs are most suitable for lossless plasmons.

Universal parameter contours predict conditions for lossless plasmon occurrence.

Abstract

We explore the potential of highly mismatched alloys (HMAs) for realizing lossless plasmonics. Systems with a plasmon frequency at which there are no interband or intraband processes possible are called lossless, as there is no 2-particle loss channel for the plasmon. We find that the band splitting in HMAs with a conduction band anticrossing guarantees a lossless frequency window. When such a material is doped, producing plasmonic behavior, we study the conditions required for the plasmon frequency to fall in the lossless window, realizing lossless plasmons. Considering a generic class of HMAs with a conduction band anticrossing, we find universal contours in their parameter space within which lossless plasmons are possible for some doping range. Our analysis shows that HMAs with heavier effective masses are most promising for realizing a lossless plasmonic material.