Spin-polarized Superconductivity and High-Chern Insulators in Twisted Rhombohedral Graphene Family

RESUMO

Rhombohedral multilayer graphene has emerged as a remarkably versatile platform for exploring strong correlation driven quantum states arising from low-energy topological flat bands. When reconstructed by the moire superlattice, these bands host a wide range of emergent novel states, including integer and fractional Chern insulators and unconventional superconductivity. Here, we firstly report the simultaneous emergence of widespread spin polarized SC and high Chern insulators in twisted bilayer multilayer RMG system 2+n where n=4,5,6. The SC states in 2+n system exhibit different responses to the in plane magnetic field, with SC being suppressed, enhanced and induced by in plane magnetic field . The latter two are consistent with spin-triplet pairing. Along with SC, angle and layer dependent HCIs with tunable Chern numbers emerge. Moreover, the fractional high Chern insulator in the system survives under high in plane magnetic field which can induce SC in the same device. Our work not only establishs twisted bilayer multilayer rhombohedral graphene as a unified platform for studying SC and high Chern insulators, but also opens a pathway towards multiple copropagating chiral Majorana channels by coupling spin-polarized SC to high Chern insulators.