Structural phase transitions in rocksalt oxides with honeycomb networks

We propose to study temperature-dependent crystal structure of Na2Co2TeO6, as well as its Ni and Zn analogs. These compounds are rocksalt oxides with honeycomb networks of 3d ions. Na atoms located between the honeycomb layers may undergo order-disorder transitions that we seek to uncover in the proposed high-resolution powder diffraction experiment. The structural information obtained therein will be crucial to reveal deformations of the magnetic honeycomb network and understand exotic magnetism of the Co and Ni compounds. Additionally, it will shed light on the ionic transport that underlies applications of these oxides as battery materials.