title: Caustics due to a negative refractive index in circular graphene p-n junctions.
abstract: We show that the wave functions form caustics in circular graphene p-n junctions which in the framework of geometrical optics can be interpreted with a negative refractive index.
authors.affiliation: Department of Physics of Complex Systems, Eötvös University, H-1117 Budapest, Pázmány Péter sétány 1/A, Hungary.
authors.forename: József
authors.initials: J
authors.lastname: Cserti
authors.forename: András
authors.initials: A
authors.lastname: Pályi
authors.forename: Csaba
authors.initials: C
authors.lastname: Péterfalvi