▎ 摘　　要

We report that a perpendicular magnetic field introduces an anomalous interaction correction, delta sigma, to the static conductivity of doped graphene in the ballistic regime. The correction implies that the magnetoresistance, delta rho(xx) scales inversely with temperature delta rho(xx)(T) proportional to 1/T in a parametrically large interval. When the disorder is scalarlike, the proportional to 1/T behavior is the leading contribution in the crossover between diffusive regime exhibiting weak localization and quantum magnetooscillations. The behavior originates from the field-induced breaking of the chiral symmetry of Dirac electrons around a single valley. The result is specific for generic two-dimensional Dirac materials which deviate from the half-filling. We conclude by proposing magnetotransport experiments, which have the capacity to detect the nature of impurities and defects in high-mobility Dirac monolayers such as recently fabricated ballistic graphene samples.