  A topological insulator (TI) interfaced with a magnetic insulator (MI) may
host an anomalous Hall effect (AHE), a quantum AHE, and a topological Hall
effect (THE). Recent studies, however, suggest that coexisting magnetic phases
in TI/MI heterostructures may result in an AHE-associated response that
resembles a THE but in fact is not. This article reports a genuine THE in a
TI/MI structure that has only one magnetic phase. The structure shows a THE in
the temperature range of T=2-3 K and an AHE at T=80-300 K. Over T=3-80 K, the
two effects coexist but show opposite temperature dependencies. Control
measurements, calculations, and simulations together suggest that the observed
THE originates from skyrmions, rather than the coexistence of two AHE
responses. The skyrmions are formed due to an interfacial DMI interaction. The
DMI strength estimated is substantially higher than that in heavy metal-based
systems.
