Theoretical limits of electron and hole doping in single layer graphene from DFT calculations

TL;DR

This paper uses DFT calculations to explore the maximum doping levels in single-layer graphene, revealing asymmetries between electron and hole doping and identifying potential superconducting regimes.

Contribution

It provides the first theoretical limits on doping levels in graphene and links these to phonon stability and superconducting potential.

Findings

Graphene can sustain up to 0.1 holes or 1.9 electrons per atom without losing stability.

Two doping levels show local maxima in superconducting critical temperature.

Electron doping exhibits a pronounced asymmetry compared to hole doping.

Abstract

Density functional theory calculations suggest a pronounced hole electron doping asymmetry in a single layer graphene. It turns out that a single graphene sheet can sustain doping levels up to 0.1 holes or up to a remarkably large 1.9 electrons per atom while maintaining dynamical [phonon] stability. Estimates of the superconducting critical temperature in the electron doped regime based on McMillans formula reveal two local maxima in the function of doping level which correlate with the local maxima of the electron phonon coupling constant.