Geometrically frustrated spin systems are known to exhibit
novel quantum phenomena. One example is the unique non-monotonic
field dependence of the magnetization and the associated emergence of
magnetization plateuas in a class of frustrated spin compounds commonly
known as the Shastry-Sutherland compounds after their underlying
magnetic lattice. In this talk, I shall discuss the underlying
mechanism for the formation of these plateaus. In the first half of the talk,
I shall compare the quantitative predictions from our recently developed unconstrained
Chern-Simons theory with experimental observations in SrCu2(BO3)2.
Interestingly, our theoretical calculations predict that at the
plateaus, the elementray magnetic excitations, triplons, form
well-defined stripes. Evidence of such stripes have recently been
reported in TmB4, another compound belonging to this family. In the second
half of the talk, I shall discuss the formation of magnetizaion plateaus in a
new family of Shastry-Sutherland compounds, viz., the rare-earth tetraborides.
The bare Shastry-Sutherland model needs to be supplemented by additional
longer range interactions to describe the magnetic properties of these compounds.
I shall discuss he underlying microscopic models and our recent studies of these
models.
