  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. We observed nonlocal resistance on the order
of 1 $\text{k}\Omega$, which obeys a scaling relation. This nonlocal resistance
evolves from the quantum Hall effect but without magnetic field/time-reversal
symmetry breaking, which is associated with a hot-spot-induced topological
valley current. This study should pave the way to developing a
Berry-phase-sensitive probe to detect hot spots in gapped Dirac materials with
inversion-symmetry breaking.
