Reinvestigation of the homogeneous spin model in YbMgGaO₄

Recently, an inelastic neutron scattering experiment on YbMgGaO₄ reported that the magnetic field can induce a phase transition between the stripe state and the AFM state. However, all existed theoretical models cannot describe this phase transition. In this talk, I will present the phase diagram of the spin model relevant to YbMgGaO₄. I find that the magnetic field can induce phase transitions between the spin liquid or stripe states and the AFM state. These phase transitions are suppressed by the next-nearest neighbor exchange interaction J₂/J₁ and vanishes as J₂/J₁>0.11. I analyze a parameter space at J₂/J₁=0.1, in which a phase transition from the spin liquid state to the AFM state can be achieved and the deviation of theoretical spin excitation energies from experimental data is only about 5.4%. My results imply that an effective homogeneous spin model still works in YbMgGaO₄.