  Various novel physical properties have emerged in Dirac electronic systems,
especially the topological characters protected by symmetry. Current studies on
these systems have been greatly promoted by the intuitive concepts of Berry
phase and Berry curvature, which provide precise definitions of the topological
orders. In this topical review, transport properties of topological insulator
(Bi2Se3), topological Dirac semimetal (Cd3As2) and topological
insulator-graphene heterojunction are presented and discussed. Perspectives
about transport properties of two-dimensional topological nontrivial systems,
including topological edge transport, topological valley transport and
topological Weyl semimetals, are provided.
