  Non-trivial topology in a two-dimensional frustrated spin system with the
Dzyaloshinskii-Moriya (DM) interaction was investigated by Monto Carlo
simulations. At finite temperatures, thermally driven topology was discovered
and was found to be dominant at low magnetic field. This topological charge has
a quadratic relation with the DM interaction and linear realtions with the
external magnetic field or the uniaxial magnetic anisotropy. We also proposed a
real frustrated system, the Mn-Bi mono-layer film with exceedingly large DM
interaction, to enable thermally driven topology. Other topological non-trivial
phases in high magnetic field region were also discussed in this real system.
