In experiments, the carrier mobility of materials is usually evaluated based on Hall effect measurements. For most semiconductors, the mobility obtained by this method (Hall mobility) is a good estimate of the drift mobility. However, in this work we find that for Dirac materials such as graphene, the ratio of Hall mobility to drift mobility, which is known as the Hall factor, cannot be simply approximated as 1, and its value varies drastically with doping concentration and temperature. We consider full electron-phonon coupling and solve the linearized Boltzmann equation (without making approximations) to derive analytical formulas for drift mobility, Hall mobility, and Hall factor of Dirac materials under arbitrary charge doping and temperature conditions. By fitting the parameters of our model through first-principles calculations, we compute the Hall factors of several common Dirac materials. The Hall factor of graphene, ${\mathrm{Be}}_3{\mathrm{C}}_2$ monolayer, ${\mathrm{VCl}}_3$ monolayer, and $\alpha$-graphyne at 300 K is determined to be 2.31, 2.76, 4.60, 1.38, respectively.

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• Electrical conductivity
• Magnetotransport
• Boltzmann theory
• First-principles calculations