  Using a model Hamiltonian approach including electron-electron interactions,
we systematically investigate the electronic structure and magnetic properties
of chiral graphene nanoribbons. We show that the presence of magnetic edge
states is an intrinsic feature of smooth graphene nanoribbons with chiral
edges, and discover a number of structure-property relations. Specifically, we
study the dependence of magnetic moments and edge-state energy splittings on
the nanoribbon width and chiral angle as well as the role of environmental
screening effects. Our results address a recent experimental observation of
signatures of magnetic ordering in chiral graphene nanoribbons and provide an
avenue towards tuning their properties via the structural and environmental
degrees of freedom.
