Quantum electronic transport in graphene: a kinetic and fluid-dynamic approach

We derive a fluid-dynamic model for electron transport near a Dirac point in graphene. Starting from a kinetic model, based on spinorial Wigner functions, the derivation of the fluid model is based on the minimum entropy principle, which is exploited to close the moment system deduced from the Wigner equation. To this aim we make two main approximations: the usual semiclassical approximation (h << 1) and a new one, namely, the 'strongly mixed state' approximation, which allow to compute the closure explicitly. Particular solutions of the fluid-dynamic equations are discussed which are of physical interest because of their connection with the Klein paradox phenomenon.