  We observe the signature of zero-field ground-state skyrmions in BiSb
topological insulator / MnGa bi-layers by using the topological Hall effect
(THE). We observe a large critical interfacial
Dzyaloshinskii-Moriya-Interaction energy (5.0 pJ/m) at the BiSb/MnGa interface
that can be tailored by controlling the annealing temperature of the MnGa
template. The THE was observed at room temperature even under absence of an
external magnetic field, which gives the strong evidence for the existence of
thermodynamically stable skyrmions in MnGa/BiSb bi-layers. Our results will
give insight into the role of interfacial DMI tailored by suitable material
choice and growth technique for generation of stable skyrmions at room
temperature.
