Signature for granular superconductivity in a multi-moiré twisted trilayer graphene

Multi-moiré systems offer a versatile platform for studying various strong correlated and topological phases. Trilayer graphene, with two distinct twist angles, θ₁₂ and θ₂₃, between the bottom two layers and the top two layers respectively, exemplifies such a system. Different combinations of these twist angles lead to flat energy bands, forming two "magic lines" in the twist-angle space. In this talk, I will present recent results from a new twisted trilayer graphene system along one of these magic lines, characterized by twist angles θ₂₃=-2θ₁₂. Here, the two moiré patterns are nearly commensurate, creating a supermoiré pattern with a period of approximately 500 nm. Using transport measurements, we identified correlated states at multiple integer fillings and two superconducting pockets between |ν|=2 and 3, where ν represents the number of electrons per moiré unit cell of the smaller twist angle. As the temperature decreases, we observe two distinct resistance drops at different critical temperatures, reminiscent of superconducting arrays. We attribute these observations to a local moiré-shift-dependent band structure, modulated within the supermoiré. Different shifts exhibit unique symmetries and band structures, resulting in the observed variations in critical temperatures. Our findings open up new possibilities for studying spatially modulated superconductivity in a highly tunable moiré platform.