Competing Orders and Superconductivity in the Doped Mott Insulator on the Shastry-Sutherland Lattice

Abstract

Quantum antiferromagnets on geometrically frustrated lattices often allow a number of unusual paramagnetic ground states. The fate of these Mott insulators upon doping is an important issue that may shed some light on the high $T_c$ cuprate problem. We consider the doped Mott insulator on the Shastry-Sutherland lattice via the $t$-$J$ model. The U(1) slave-boson mean-field theory reveals the strong competition between different broken symmetry states. It is found that, in some ranges of doping, there exist superconducting phases with or without coexisting translational-symmetry-breaking orders such as the staggered flux or dimerization. Our results will be directly relevant to $\mathrm{S}\mathrm{r}{\mathrm{C}\mathrm{u}}_2({\mathrm{B}\mathrm{O}}_3{)}_2$ when this material is doped in future.