Magnetic phase diagram of the quasi-2D honeycomb antiferromagnet Na2Co2TeO6 single crystal

The layered compound Na2Co2TeO6 is a model honeycomb compound having a zigzag antiferromagnetic (AFM) ground state. Na2Co2TeO6 poses a rich magnetic phase diagram in the H-T plane. The zigzag antiferromagnet is predicted within the framework of (i) the frustrated J1-J2-J3 Heisenberg model and (ii) the Kitaev-Heisenberg model. Field induced exotic AFM star, zigzag star, and AFM vortex states are predicted for the Kitaev-Heisenberg model in contrast to canted zigzag state for the Heisenberg model. We propose single crystal neutron diffraction study on Na2Co2TeO6 as a function of H and T using the WISH diffractometer to determine the magnetic phase diagram and the spin model. The present study aims to have an experimental realization of the possible Kitaev-Heisenberg model (realized only in the compounds with 4d and 5d elements) in a compound with 3d7 (Co2+) ions.