Field-Induced Quantum Phases in Frustrated Spin-Dimer Model: A Sign-Problem-Free Quantum Monte Carlo Study

The magnetization process of a frustrated spin-1/2 spin-dimer model on a square lattice is investigated by means of a sign-problem-free quantum Monte Carlo algorithm developed recently. Rich field-induced quantum phases are discovered. We find two spin superfluids satisfying different symmetries upon layer permutation. There exist as well two solid phases with distinct checkerboard patterns. Besides, two kinds of spin supersolids are observed over a finite regime of magnetic fields. The latter two phases can be stabilized when small but nonzero spin anisotropy is present. Various field-induced transitions among these phases are explored. Our findings may provide guidance to the search of these interesting quantum phases in real frustrated spin-dimer compounds.