Band structures of plasmonic polarons

TL;DR

This paper demonstrates through advanced many-body calculations that electron-plasmon interactions create distinct plasmonic polaron bands in the electronic structures of semiconductors, broadening and blueshifting the valence bands.

Contribution

It introduces the concept of plasmonic polaron bands in band structures, showing they are a general feature in systems with well-defined plasmon resonances, supported by first-principles calculations.

Findings

Plasmonic polaron bands appear in silicon and transition metal dichalcogenide monolayers.

These bands follow the dispersion of valence bands but are broadened and blueshifted.

Criteria are proposed for observing these bands in photoelectron spectra.

Abstract

Using state-of-the-art many-body calculations based on the `GW plus cumulant' approach, we show that electron-plasmon interactions lead to the emergence of plasmonic polaron bands in the band structures of common semiconductors. Using silicon and group IV transition metal dichalcogenide monolayers (AX2 with A=Mo,W and X=S,Se) as prototypical examples, we demonstrate that these new bands are a general feature of systems characterized by well defined plasmon resonances. We find that the energy vs. momentum dispersion relations of these plasmonic structures closely follow the standard valence bands, although they appear broadened and blueshifted by the plasmon energy. Based on our results we identify general criteria for observing plasmonic polaron bands in the angle-resolved photoelectron spectra of solids.