paper

Transition to the Haldane phase driven by electron-electron correlations

arXiv:2304.11154 · doi:10.1038/s41467-023-44135-9

Abstract

One of the most famous quantum systems with topological properties, the spin antiferromagnetic Heisenberg chain, is well-known to display exotic edge states. However, this spin model has not been analyzed from the more general perspective of strongly correlated systems varying the electron-electron interaction strength. Here, we report the investigation of the emergence of the Haldane edge in a system of interacting electrons -- the two-orbital Hubbard model -- with increasing repulsion strength and Hund interaction . We show that interactions not only form the magnetic moments but also form a topologically nontrivial fermionic many-body ground-state with zero-energy edge states. Specifically, upon increasing the strength of the Hubbard repulsion and Hund exchange, we identify a sharp transition point separating topologically trivial and nontrivial ground-states. Surprisingly, such a behaviour appears already at rather small values of the interaction, in a regime where the magnetic moments are barely developed.

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