Spin-orbit physics of j=1/2 Mott insulators on the triangular lattice

Michael Becker

University of Cologne, Institute for Theoretical Physics, Cologne, Germany

We investigate the Heisenberg-Kitaev model on the triangular lattice which is thought to capture the essential physics of the spin-orbital entanglement in a broad class of effective j=1/2 Mott insulators such as certain Iridate compounds - one potential candidate material being the recently synthesized Ba3IrTi2O9. While first results have recently been reported for the classical limit of this model, our focus is on its quantum version. Using a combination of numerical techniques, such as exact diagonalization and the density matrix renormalization group, which we complement with various analytical approaches, we can identify its entire phase diagram. The most interesting features of this phase diagram resemble what has already been found in the classical limit - a Z2 vortex lattice phase in the vicinity of the Heisenberg limit and a "nematic" phase around the antiferromagnetic Kitaev point.

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