Superconductivity, Anomalous Hall Effect, and Stripe Order in Rhombohedral Hexalayer Graphene

Abstract: Unconventional superconducting phases are distinguished by broken symmetries in their order parameters. Here, we report the discovery of an exotic superconducting phase in rhombohedral hexalayer graphene at high displacement fields, marked by its coexistence with both a stripe charge order and the anomalous Hall effect. In angle-resolved transport measurements, the onset of stripe order is manifested as thermally activated insulating behavior along one axis, with highly conductive transport along the orthogonal direction. Upon cooling, superconductivity emerges exclusively along the high-conductivity axis, forming one-dimensional-like superconducting channels. This anisotropic superconducting phase exhibits multiple first-order hysteretic transitions. Pronounced thermal hysteresis-between warming and cooling across the superconducting transition-suggests a melting transition of the underlying stripe phase. Additionally, magnetic-field-induced switching-similar to phenomena reported in tetra- and pentalayer graphene-supports the chiral nature of the superconducting state. Together, these findings identify a previously unrecognized quantum phase: a chiral superconductor embedded within a stripy Hall crystal.