Field-induced Spin Liquid-like State in a Magnetic Honeycomb Lattice*

Quantum fluctuations in magnetic lattices can yield a quantum spin liquid (QSL) state, where no long-range order appears even at zero temperature. The variety of mechanisms that can generate the spin liquid state and the more exotic QSL state remain unclear, however. Here, we report a new magnetic honeycomb system, BaCo₂(P_1-xV_x)₂O₈, in which the spin correlations can be tuned by the disorder, leading to different magnetic behaviors. At low x, the material has a spin glass ground state that appears to be due to coexisting and competing correlations. We have found that an external magnetic field can introduce spin liquid-like behavior for some members of the solid solution, testified by the magnetic and thermodynamic experiments. Our results suggest that structural geometry, chemical disorder and external field may help enhance quantum fluctuations in magnetic honeycomb materials.