Kitaev Interactions in the Co Honeycomb Antiferromagnets Na3Co2SbO6 and Na2Co2TeO6

Published

December 24, 2020

Author(s)

M. Songvilay, J. Robert, Jose Rodriguez Rivera, William D. Ratcliff, F. Damay, V. Baledent, M. Jimenez-Ruiz, P. Lejay, E. Pachoud, A. Hadj-Azzem, V. Simonet, C. Stock

Abstract

Co²⁺ ions in an octahedral crystal field, stabilize a jeff = 1⁄2 ground state with an orbital degree of freedom and and have been recently put forward for realising Kitaev interactions, a prediction that we have tested by investigating spin dynamics in two cobalt honeycomb lattice compounds, Na₂Co₂TeO₆ and Na₃Co₂SbO₆, using inelastic neutron scattering. The measurements were performed on polycrystalline samples and modeled using linear spin wave theory. Our results show that the magnetic excitations of these compounds can be reproduced with a spin Hamiltonian including a dominant Kitaev nearest-neighbor interaction, weaker Heisenberg interactions up to the third neighbor and bond-dependent off-diagonal exchange interactions. Beyond the Kitaev interaction that alone would induce a quantum spin liquid state, the presence of these additional couplings is responsible for the zigzag-type long-range magnetic ordering observed at low temperature in both compounds. These results provide evidence for the realization of Kitaev-type coupling in cobalt-based materials, despite hosting a weaker spin-orbit coupling than their 4d and 5d counterparts.

Citation

Physical Review B

Volume

102

Issue

22

Pub Type

Journals

Keywords

Kitaev, neutron

Citation

Songvilay, M. , Robert, J. , Rodriguez, J. , Ratcliff, W. , Damay, F. , Baledent, V. , Jimenez-Ruiz, M. , Lejay, P. , Pachoud, E. , Hadj-Azzem, A. , Simonet, V. and Stock, C. (2020), Kitaev Interactions in the Co Honeycomb Antiferromagnets Na₃Co₂SbO₆ and Na₂Co₂TeO₆, Physical Review B (Accessed December 16, 2024)