Seminarium Fizyki Materii Skondensowanej

In this work we investigate the topological properties of selenium and tellurium chains. We postulate a realistic model which includes spin-orbit interaction. This model is topologically non-trivial, with a topological invariant protected by a crystalline symmetry. We describe the end states, which are orbitally polarized, with an orbital density modulation strongly peaked at the edge. Investigating further, we propose a model with a simplified but related geometry. This model, which is computationally simpler, decomposes into three SSH-3 chains allowing us to relate the invariant of a chalcogen chain to that of the SSH-3 model with an additional crystalline symmetry. We contrast this result with that recently obtained for a $p$-orbital zigzag chain on a plane -- the orbital SSH model.