Colossal Magnetoresistance in Twisted Intertwined Graphene Spirals

Colossal magnetoresistance (CMR) is highly applicable in spintronic devices such as magnetic sensors, magnetic memory, and hard drives. Typically, CMR is found in Weyl semimetals characterized by perfect electron-hole symmetry or exceptionally high electric conductivity and mobility. Our study explores this phenomenon in a recently developed graphene moir$\acute{e}$ system, which demonstrates CMR owing to its topological structure and high-quality crystal formation. We specifically investigate the electronic properties of three-dimensional (3D) intertwined twisted graphene spirals (TGS), manipulating the screw dislocation axis to achieve a rotation angle of 7.3$^{\circ}$. Notably, at 14 T and 2 K, the magnetoresistance of these structures reached 1.7$\times$10$^7$%, accompanied by an unexpected metal-to-insulator transition as the temperature increased. This transition becomes noticeable when the magnetic field exceeds a minimal threshold of approximately 0.1 T. These observations suggest the existence of complex, correlated states within the partially filled three-dimensional Landau levels of the 3D TGS system. Our findings open up new possibilities for achieving CMR by engineering the topological structure of 2D layered moir$\acute{e}$ systems.