Dynamics of the particle - hole pair creation in graphene

TL;DR

This paper provides a detailed theoretical analysis of particle-hole pair creation in graphene under electric fields, revealing a universal resistivity, revising the conductivity value, and connecting to experimental observations.

Contribution

It offers a quantitative description of pair creation dynamics in graphene, including effects of temperature and disorder, and discusses Bloch oscillations within a tight-binding framework.

Findings

Universal finite resistivity in pure graphene without dissipation

Revised DC conductivity value of πe²/2h, matching optical frequency measurements

Temperature and charge puddles influence on pair creation and conductivity

Abstract

The process of coherent creation of particle - hole excitations by an electric field in graphene is quantitatively described. We calculate the evolution of current density, number of pairs and energy after switching on the electric field. In particular, it leads to a dynamical visualization of the universal finite resistivity without dissipation in pure graphene. We show that the DC conductivity of pure graphene is rather $\frac{\pi e^{2}}{2 h}$ than the often cited value of $\frac{4 e^{2}}{\pi h}$. This value coincides with the AC conductivity calculated and measured recently at optical frequencies. The effect of temperature and random chemical potential (charge puddles) are considered and explain the recent experiment on suspended graphene. A possibility of Bloch oscillations is discussed within the tight binding model.