Emergent Superconductivity in the weak Mott insulator phase of bilayer Graphene Moir\'e Superlattice

TL;DR

This paper offers a phenomenological explanation for the emergence of superconductivity within the weak Mott insulator phase of twisted bilayer graphene, highlighting its unique two-dimensional nature and comparing with existing theories.

Contribution

It introduces a new understanding of superconductivity emergence in weak Mott insulators of bilayer graphene, emphasizing the role of 2D effects and providing a comparative analysis with other models.

Findings

Resistivity first increases then drops to zero at low temperatures.

Superconductivity appears within the weak Mott insulator phase.

The phenomenon is attributed to the pure two-dimensional nature of the system.

Abstract

We propose a phenomenological understanding of the recently discovered weak Mott insulator in the moir\'e superlattice of twisted bilayer graphene, especially the emergent superconductivity at low temperature within the weak Mott insulator phase, namely while lowering temperature, the longitudinal resistivity first grows below temperature $T_m$, but then rapidly drops to zero at even lower temperature $T_c$. An emergent superconductor in an insulator phase is very unusual. Here we propose that this phenomenon is due to the pure two-dimensional nature of the bilayer graphene moir\'e superlattice. We also compare our results with other theories proposed so far.