Hidden chiral symmetry protected $\mathbb{Z}\oplus \mathbb{Z}$ topological insulators in a ladder dimer model

Jin-Yu Zou, Bang-Gui Liu

We construct a two-leg ladder dimer model by using two orbitals instead of one in Su-Schrieffer-Heeger (SSH) dimer chain and find out a chiral symmetry in it. In this model, the ot…