Terahertz and gigahertz magnetoratchets in graphene-based two-dimensional metamaterials

Here, the authors study the ratchet effect -- the conversion of alternating fields in the terahertz and gigahertz range into direct current -- using a 2D metamaterial formed by monolayer graphene and a nearby gate with an array of triangular holes. A combined experimental and theoretical study shows that application of magnetic field leads to giant enhancement of the ratchet current and emergence of quantum magneto-oscillations, also featuring a complex Fano shape of the cyclotron resonance and well-pronounced electron spin resonance.