# Electron and hole lifetime in monolayer graphene

## TL;DR

This paper investigates the Coulomb decay rates of excited electrons and holes in monolayer graphene, revealing unique decay behaviors influenced by plasmon modes and energy levels, with implications for understanding quasiparticle dynamics.

## Contribution

It provides a detailed analysis of Coulomb decay mechanisms in monolayer graphene, highlighting the role of plasmon modes and energy dependence, which was not thoroughly characterized before.

## Key findings

- Low-lying valence holes decay rapidly via undamped acoustic plasmons.
- Conduction electrons and holes at low energy behave like a 2D electron gas.
- Higher-energy states show similar decay channels and wave vector dependence.

## Abstract

Excited conduction electrons, conduction holes, and valence holes in monolayer electron-doped graphene exhibit unusual Coulomb decay rates. The deexcitation processes are studied using the screened exchange energy. They might utilize the intraband single-particle excitations (SPEs), the interband SPEs, and the plasmon modes, depending on the quasiparticle states and the Fermi energies. The low-lying valence holes can decay through the undamped acoustic plasmon, so that they present very fast Coulomb deexcitations, nonmonotonous energy dependence, and anisotropic behavior. However, the low-energy conduction electrons and holes are similar to those in a two-dimensional electron gas. The higher-energy conduction states and the deeper-energy valence ones behave similarly in the available deexcitation channels and have a similar dependence of decay rate on the wave vector ${\bf k}$.