  The Shastry-Sutherland lattice, one of the simplest systems with geometric
frustration, which has an exact eigenstate by putting singlets on diagonal
bonds, can be realized in a group of layered compounds and rises both
theoretical and experimental interest. Most of the previous studies on the
Shastry-Sutherland lattice are focusing on the Heisenberg model. Here we opt
for the Hubbard model to calculate phase diagrams over a wide range of
interaction parameters, and show the competing effects of interaction,
frustration and temperature. At low temperature, frustration is shown to favor
a paramagnetic metallic ground state, while interaction drives the system to an
antiferromagnetic insulator phase. Between these two phases, there are an
antiferromagnetic metal phase and a paramagnetic insulator (which should be a
valence bond solid) phase resulting from the competition of the frustration and
the interaction. Our results may shed light on more exhaustive studies about
quantum phase transitions in this lattice.
