Signature of chiral anomaly in a graphene-based heterostructure

Abstract

Chiral anomaly is a fundamental manifestation of topological matter caused by chirality imbalance. It can be of great practical value by providing a mechanism for dissipationless transport. The phenomenon is highly sensitive to the system dimensionality, disappearing in the 2D limit. Different schemes have been proposed to observe the chiral anomaly in graphene-based systems but experimental evidence has been lacking. Here, we synthesized two types of the Gr/Sr/SiC nanostructure - with 2D and 3D, bulk-like, layers of Sr - the difference being the amount of Sr intercalated under graphene. In contrast to the 2D material, 3D Gr/Sr/SiC exhibits a signature of the chiral anomaly - quadratic negative magnetoresistance in parallel magnetic and electric fields. Also, the functional form of the temperature dependence of the magnetoresistance agrees with the chiral anomaly. In addition, the 3D heterostructure exhibits suppressed conductivity and quantum oscillations in graphene. These effects may be associated with the graphene layer incorporated into a complex 3D heterostructure. Hopefully, the discovered signature of chiral anomaly in the built-in graphene would spur research on the phenomenon in topological nanomaterials.