Selective transmission of Dirac electrons and ballistic   magnetoresistance of \textit{n-p} junctions in graphene
  We show that an electrostatically created n-p junction separating the electron and hole gas regions in a graphene monolayer transmits only those quasiparticles that approach it almost perpendicularly to the n-p interface. Such a selective transmission of carriers by a single n-p junction would manifest itself in non-local magnetoresistance effect in arrays of such junctions and determines the unusual Fano factor in the current noise universal for the n-p junctions in graphene. 
Vadim V. Cheianov and Vladimir I. Fal'ko