arXiv:1606.04297 · Physical review. B./Physical review. B
Haldane insulator protected by reflection symmetry in the doped Hubbard model on the three-legged ladder
H. L. Nourse, Ian P. McCulloch, C. Janani, Benjamin James Powell
Abstract
We demonstrate the existence of an insulating phase in the three-legged Hubbard ladder at two-thirds filling. In this phase chargons are bound because the physics within a unit cell favors the formation of triplets. The resultant moments lead to a ground state in the Haldane phase, a symmetry protected topological state of matter. In this purely fermionic model, reflection is protecting but time-reversal and dihedral symmetries are not, in contrast to spin models.