Polaronic signatures and spectral properties of graphene antidot lattices

TL;DR

This paper investigates how electron-phonon interactions influence the spectral properties of graphene antidot lattices, revealing significant polaronic effects and mass enhancement, with implications for future spectroscopic experiments.

Contribution

It provides a detailed analysis of momentum-dependent electron-phonon coupling and its impact on quasiparticle properties in graphene antidot lattices, highlighting polaronic behavior.

Findings

Large electron-phonon mass enhancement observed.

Momentum dependence favors small phonon momentum scattering.

Results applicable to future ARPES measurements.

Abstract

We explore the consequences of electron-phonon (e-ph) coupling in graphene antidot lattices (graphene nanomeshes), i.e., triangular superlattices of circular holes (antidots) in a graphene sheet. They display a direct band gap whose magnitude can be controlled via the antidot size and density. The relevant coupling mechanism in these semiconducting counterparts of graphene is the modulation of the nearest-neighbor electronic hopping integrals due to lattice distortions (Peierls-type e-ph coupling). We compute the full momentum dependence of the e-ph vertex functions for a number of representative antidot lattices. Based on the latter, we discuss the origins of the previously found large conduction-band quasiparticle spectral weight due to e-ph coupling. In addition, we study the nonzero-momentum quasiparticle properties with the aid of the self-consistent Born approximation, yielding results that can be compared with future angle-resolved photoemission spectroscopy measurements. Our principal finding is a significant e-ph mass enhancement, an indication of polaronic behavior. This can be ascribed to the peculiar momentum dependence of the e-ph interaction in these narrow-band systems, which favors small phonon momentum scattering. We also discuss implications of our study for recently fabricated large-period graphene antidot lattices.