First-principles study of the Ir-Ir dimerization effect on the magnetic phase diagram of honeycomb iridates

Honeycomb lattice iridates have been a promising candidate for the realization of the Kitaev spin model. However, the addition of off-diagonal and Heisenberg interactions result in magnetic ordering at low temperatures, causing the quantum spin liquid (QSL) phase to remain elusive. The application of hydrostatic pressure to the system has shown the loss of magnetic ordering, and although indicative of a spin liquid phase, has been shown to be caused by dimerization between iridium ions. Using ab initio calculations, we intend to identify the pressure region in beta-Li₂IrO₃ and alpha-Na₂IrO₃ where the symmetry lowers in the systems, marking the onset of dimerization. Subsequently, using exact diagonalization (ED) and cluster mean field theory (CMFT) on a periodic cluster, we will identify the ground state of the dimerized system and explore its phase diagram and spin correlations.