  Discoveries of interfacial topological Hall effect (THE) provide an ideal
platform for exploring physics arising from the interplay between topology and
magnetism. The interfacial topological Hall effect is closely related to the
Dzyaloshinskii-Moriya interaction (DMI) at interface and topological spin
textures. However, it is difficult to achieve a sizable THE in heterostructures
due to the stringent constraints on the constituents of THE heterostructures
such as strong spin-orbit coupling (SOC). Here we report the observation of a
giant THE signal of 1.39 $\mu\Omega\cdot$cm in the van der Waals
heterostructures of CrTe2/Bi2Te3 fabricated by molecular beam epitaxy, a
prototype of two-dimensional (2D) ferromagnet (FM)/topological insulator (TI).
This large magnitude of THE is attributed to an optimized combination of 2D
ferromagnetism in CrTe2, strong SOC in Bi2Te3, and an atomically sharp
interface. Our work reveals CrTe2/Bi2Te3 as a convenient platform for achieving
large interfacial THE in hybrid systems, which could be utilized to develop
quantum science and high-density information storage.
