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arXiv · 2303.08464

A $\mathbb{Z}_2$ invariant for chiral and particle-hole symmetric topological chains

Domenico Monaco·Gabriele Peluso
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Abstract

We define a $\mathbb{Z}_2$-valued topological and gauge invariant associated to any 1-dimensional, translation-invariant topological insulator which satisfies either particle-hole symmetry or chiral symmetry. The invariant can be computed from the Berry phase associated to a suitable basis of Bloch functions which is compatible with the symmetries. We compute the invariant in the Su-Schrieffer-Heeger model for chiral symmetric insulators, and in the Kitaev model for particle-hole symmetric insulators. We show that in both cases the $\mathbb{Z}_2$ invariant predicts the existence of zero-energy boundary states for the corresponding truncated models.

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Domenico Monaco, Gabriele Peluso. 2023-03-15. A $\mathbb{Z}_2$ invariant for chiral and particle-hole symmetric topological chains. https://doi.org/10.1063/5.0138647

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