Abstract
We derive and study a spin one-half Hamiltonian on a honeycomb lattice describing the exchange interactions between ions in a family of layered iridates (). Depending on the microscopic parameters, the Hamiltonian interpolates between the Heisenberg and exactly solvable Kitaev models. Exact diagonalization and a complementary spin-wave analysis reveal the presence of an extended spin-liquid phase near the Kitaev limit and a conventional Néel state close to the Heisenberg limit. The two phases are separated by an unusual stripy antiferromagnetic state, which is the exact ground state of the model at the midpoint between two limits.
- Received 16 April 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.027204
©2010 American Physical Society