Electronic Cooling in Graphene

TL;DR

This paper investigates the cooling mechanisms of electrons in graphene, revealing how acoustic and optical phonons influence temperature decay under different doping conditions and highlighting unique power law behaviors.

Contribution

It provides a detailed analysis of electron cooling in graphene, emphasizing the roles of acoustic and optical phonons and their effects on temperature decay.

Findings

Far from equilibrium, electronic temperature decays as a power law due to weak acoustic phonon cooling.

In heavily doped graphene, high electronic temperature decreases linearly with time, proportional to n^(3/2).

Optical phonons' role in cooling is discussed relative to acoustic phonons.

Abstract

Energy transfer to acoustic phonons is the dominant low-temperature cooling channel of electrons in a crystal.For cold neutral graphene we find that the weak cooling power of its acoustical modes relative to the heat capacity of the system leads to a power law decay of the electronic temperature when far from equilibrium. For heavily doped graphene a high electronic temperature is shown to initially decrease linearly with time at a rate proportional to n^(3/2) with n being the electronic density. We discuss the relative importance of optical and acoustic phonons to cooling.