Chiral superconductivity in rhombohedral hexalayer graphene

Rhombohedral multilayer graphene has recently emerged as a versatile platform for exploring unconventional superconductivity. In particular, chiral superconductivity arising from a spin valley polarized quarter metal phase has been observed in tetra and pentalayer rhombohedral graphene, opening a pathway toward realizing Majorana fermions and establishing an important platform for topological physics and fault-tolerant quantum computing. However, the influence of detailed band-structure evolution with layer number, including the shape of the Fermi surface, lifting of spin and valley degeneracies, and the evolution of these symmetry broken states within the chiral superconducting phase, remains unresolved. Here, we report the observation of robust chiral superconducting phases in electron doped rhombohedral hexalayer graphene under a large displacement field, in the absence of moiré superlattice effects. Similar to the tetra and pentalayer cases, the longitudinal resistance in both chiral superconducting regimes exhibits magnetic hysteresis upon sweeping the out-of-plane magnetic field B⊥. Moreover, the superconductivity is remarkably robust against exceptionally high critical fields in both in-plane and out-of-plane directions. These observations reinforce the universality of chiral superconductivity in the rhombohedral multilayer graphene family and establish this system as an ideal platform for realizing and studying exotic phases of matter.