Majorana signature in a diatomic Kitaev chain with dual non-Hermitian mechanisms

The band structure of a one-dimensional nonreciprocal diatomic Kitaev chain is investigated by introducing anti- P T -symmetric imaginary potentials with the configuration ( i γ , − i γ , − i γ , i γ ) , where γ denotes the strength of the imaginary potential. It is found that non-Hermitian parameters and the modification of the unit cell induce multiple topological phase transitions in the system. When the chemical potential is set at zero energy, this system exhibits two purely real Majorana zero modes (MZMs) and four purely imaginary Su–Schrieffer–Heeger (SSH) edge modes, accompanied by a “Majorana-mixed-SSH” topological phase transition. In contrast, as the chemical potential deviates from zero, both Majorana modes and SSH edge modes emerge at finite imaginary potential strengths, and a phase transition from the SSH phase to the Majorana phase is observed. We argue that the modulating effect of non-Hermitian parameters on edge modes demonstrated in this work can provide theoretical support for understanding phase transitions and the generation of Majorana modes in non-Hermitian topological superconducting systems.