Fermionic Symmetry-Protected Topological Phase in a Two-Dimensional Hubbard Model
Abstract
We study the two-dimensional (2D) Hubbard model using exact diagonalization for spin-1/2 fermions on the triangular and honeycomb lattices decorated with a single hexagon per site. In certain parameter ranges, the Hubbard model maps to a quantum compass model on those lattices. On the triangular lattice, the compass model exhibits collinear stripe antiferromagnetism, implying -density wave charge order in the original Hubbard model. On the honeycomb lattice, the compass model has a unique, quantum disordered ground state that transforms nontrivially under lattice reflection. The ground state of the Hubbard model on the decorated honeycomb lattice is thus a 2D fermionic symmetry-protected topological phase. This state -- protected by time-reversal and reflection symmetries -- cannot be connected adiabatically to a free-fermion topological phase.
Cite
@article{arxiv.1603.03439,
title = {Fermionic Symmetry-Protected Topological Phase in a Two-Dimensional Hubbard Model},
author = {Cheng-Chien Chen and Lukas Muechler and Roberto Car and Titus Neupert and Joseph Maciejko},
journal= {arXiv preprint arXiv:1603.03439},
year = {2016}
}
Comments
Original: 5+3 pages, 4+2 figures, including the supplemental material. Revised: updated title, content, and references in version 2