Asymmetric Proximity Effects in WSe ₂ -Cladded twisted double bilayer graphene

Abstract Twisted double bilayer graphene (TDBG) offers a versatile platform for exploring strongly correlated and topological phases. Recent studies have shown that placing a WSe 2 substrate on one side of TDBG enriches the phase diagram by inducing superconductivity. However, the underlying mechanism and the precise role of WSe 2 are not fully understood. In this work, we fabricate a nominally symmetric TDBG structure with twisted angle θ = 1.36°, sandwiched between two WSe 2 layers. Despite this structural symmetry, the system exhibits a striking electronic asymmetry: the phase diagrams of correlated insulators, high-field Chern insulators, and signature of superconductivity all depend strongly on the direction of the applied displacement field, D . This reveals a profound and unexpected tunability of correlated states via the subtle interplay of WSe₂ proximity effects. Our results provide new insights into the manipulation of correlated phases in TDBG and advance the understanding of its superconductivity.