Quantum phases in a doped Mott insulator on the Shastry-Sutherland lattice

TL;DR

This paper proposes a projected BCS wave function as the ground state for doped SrCu2(BO3)2 on the Shastry-Sutherland lattice, revealing distinct electronic phases upon electron and hole doping, including an unusual metal and d-wave RVB superconductivity.

Contribution

It introduces a novel wave function approach to model doped Mott insulators on the Shastry-Sutherland lattice, capturing asymmetric doping effects and emergent superconducting states.

Findings

Electron doping leads to an unusual metallic state with valence bond correlations.

Hole doping results in d-wave RVB superconductivity with enhanced pairing due to bond order.

The wave function exactly reproduces the ground state at half filling.

Abstract

We propose the projected BCS wave function as the ground state for the doped Mott insulator SrCu2(BO3)2 on the Shastry-Sutherland lattice. At half filling this wave function yields the exact ground state. Adding mobile charge carriers, we find a strong asymmetry between electron and hole doping. Upon electron doping an unusual metal with strong valence bond correlations forms. Hole doped systems are d-wave RVB superconductors in which superconductivity is strongly enhanced by the emergence of inhomogeneous plaquette bond order.