Topological Valley Currents in Bilayer Graphene/Hexagonal Boron Nitride Superlattices

Understand

Graphene superlattices have recently been attracting growing interest as an emergent class of quantum metamaterials.

• In this paper, we report the observation of nonlocal transport in bilayer graphene (BLG) superlattices encapsulated between two hexagonal boron nitride (hBN) layers, which formed hBN/BLG/hBN moir\'e superlattices.
• We then employed these superlattices to detect a long-range charge-neutral valley current using an all-electrical method.
• The moir\'e superlattice with broken inversion symmetry leads to a hot spot with Berry curvature accumulating at the charge neutral point (CNP), and it harbors satellites of the CNP.