Theory and Computation of Hall Scattering Factor in Graphene.

Macheda, Francesco; Poncé, Samuel; Giustino, Feliciano; Bonini, Nicola · Nano Lett · 2020

basic_science · Level V

Where this comes from

Abstract

The Hall scattering factor, <i>r</i>, is a key quantity for establishing carrier concentration and drift mobility from Hall measurements; in experiments, it is usually assumed to be 1. In this paper, we use a combination of analytical and <i>ab initio</i> modeling to determine <i>r</i> in graphene. Although at high carrier densities <i>r</i> ≈ 1 in a wide temperature range, at low doping the temperature dependence of <i>r</i> is very strong with values as high as 4 below 300 K. These high values are due to the linear bands around the Dirac cone and the carrier scattering rates due to acoustic phonons. At higher temperatures, <i>r</i> can instead become as low as 0.5 due to the contribution of both holes and electrons and the role of optical phonons. Finally, we provide a simple analytical model to compute accurately <i>r</i> in graphene in a wide range of temperatures and carrier densities.