# Topological phase and lattice structures in spin chain models

## TL;DR

This paper explores the topological phases in spin chain models, revealing that non-trivial topological phases can arise from anisotropy and bond parity, expanding understanding of topological invariants in these systems.

## Contribution

It demonstrates that topologically non-trivial phases are influenced by anisotropy and bond parity, not just periodicity, providing new insights into topological invariants in spin chain models.

## Key findings

- TNP can exist under various model conditions including anisotropy.
- Parity of bond types influences the formation of TNP.
- Topological invariant relates to bond parity rather than periodicity.

## Abstract

Finding new topological materials and understanding the physical essence of topology are crucial problems for researchers. We studied the topological property based on several proposed Su-Schrieffer-Heeger (SSH) related models. We show that the topologically non-trivial phase (TNP) in the SSH model can exist in other model conditions and can even be caused by anisotropy; its origin has a close relation with the even-bond dimerization. Further study shows that the TNP is not determined by the periodicity of the system, but the parity of the two kinds of bonds plays a significant role for the formation of the TNP. This finding reveals the topological invariant of the system and might supply potential extended topological materials for both theoretical and experimental researches.