Mott transition and Antiferromagnetic Metal on Shastry-Sutherland   Lattice
  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. 
Hai-Di Liu, Yao-Hua Chen, Heng-Fu Lin, Hong-Shuai Tao, Wu-Ming Liu
cond-mat.str-el