Affleck-Kennedy-Lieb-Tasaki State on a Honeycomb Lattice from t2g Orbitals

Maciej Koch-Janusz, D. I. Khomskii, Eran Sela

Research output: Contribution to journalArticlepeer-review


The two-dimensional Affleck-Kennedy-Lieb-Tasaki (AKLT) model on a honeycomb lattice has been shown to be a universal resource for quantum computation. In this valence bond solid, however, the spin interactions involve higher powers of the Heisenberg coupling (S→i·S→j)n, making these states seemingly unrealistic on bipartite lattices, where one expects a simple antiferromagnetic order. We show that those interactions can be generated by orbital physics in multiorbital Mott insulators. We focus on t2g electrons on the honeycomb lattice and propose a physical realization of the spin-3/2 AKLT state. We find a phase transition from the AKLT to the Néel state on increasing Hund's rule coupling, which is confirmed by density matrix renormalization group simulations. An experimental signature of the AKLT state consists of protected, free S=1/2 spins on lattice vacancies, which may be detected in the spin susceptibility.

Original languageEnglish
Article number247204
JournalPhysical Review Letters
Issue number24
StatePublished - 18 Jun 2015


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