Projective symmetry group classification of chiral Z(2) spin liquids on the pyrochlore lattice: Application to the spin-1/2 XXZ Heisenberg model

We give a complete classification of fully symmetric as well as chiral Z(2) quantum spin liquids on the pyrochlore lattice using a projective symmetry group analysis of Schwinger boson mean-field states. We find 50 independent Ansatze, including the 12 fully symmetric nearest-neighbor Z(2) spin liquids that have been classified by Liu et al. [Phys. Rev, 11 100, 075125 (2019)]. For each class, we specify the most general symmetry-allowed mean-field Hamiltonian. Additionally, we test the properties of a subset of the spin-liquid Ansatze by solving the mean-field equations for the spin-1/2 XXZ model near the antiferromagnetic Heisenberg point. We find four chiral spin liquids that break the screw symmetry of the lattice modulo time-reversal symmetry. These states have a different symmetry from the previously studied monopole flux state, and their unique characteristic is a pi/3 flux enclosed by every rhombus of the lattice.