  The celebrated Shastry Sutherland model has a gapped dimer singlet ground
state. The material SrCu$_2$(BO$_3$)$_2$ serves as a good realization of this
model, upto small anisotropies arising from Dzyaloshinskii-Moriya (DM)
interactions. The DM interactions admix a triplet component into the singlet
ground state and give rise to weakly dispersing triplon bands. We show that an
applied magnetic field splits the triplon modes and opens band gaps.
Surprisingly, we are left with topological bands with Chern numbers $\pm 2$.
SrCu$_2$(BO$_3$)$_2$ thus supports topologically protected triplonic edge modes
and is a magnetic analogue of the integer quantum Hall effect. At a critical
value of the magnetic field set by the strength of DM interactions, the three
triplon bands touch once again in a spin-1 generalization of a Dirac cone, and
lose their topological character. We predict a strong thermal Hall signature in
the topological regime.
