Non-Hermitian systems can host topological states with unusual topological invariants and bulk-edge correspondences that are distinct from conventional Hermitian systems. Here we show that two unique classes of non-Hermitian two-dimensional topological phases, a $2\mathbb{Z}$ non-Hermitian Chern insulator and a ${\mathbb{Z}}_2$ topological semimetal, can be realized by solely tuning staggered non-Hermitian or asymmetric hopping strengths in a one-dimensional (1D) superlattice. These non-Hermitian topological phases support real edge modes due to robust $\mathcal{PT}$-symmetric-like spectra and can coexist in a certain parameter regime. The proposed phases can be experimentally realized in photonic or atomic systems and may open an avenue for exploring unique classes of non-Hermitian topological phases with 1D superlattices.

中文翻译：

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一维超晶格中非对称跳跃引起的二维非Hermitian拓扑相

非Hermitian系统可以容纳具有与常规Hermitian系统不同的异常拓扑不变量和体边缘对应关系的拓扑状态。在这里，我们显示了非Hermitian二维拓扑相的两个独特类，$\mathrm{2个}\mathbb{ž}$ 非赫米特陈绝缘子和 ${\mathbb{ž}}_{\mathrm{2个}}$拓扑半金属可以通过仅调整一维（1D）超晶格中交错的非Hermitian或非对称跳跃强度来实现。由于健壮性，这些非Hermitian拓扑阶段支持实边缘模式$\mathcal{PT}$类对称谱，并可以在某个参数范围内共存。提议的相可以在光子或原子系统中通过实验实现，并且可以为探索具有一维超晶格的非Hermitian拓扑相的独特类别开辟一条途径。