Edge states and skin effect dependent electron transport properties of a non-Hermitian Su-Schrieffer-Heeger chain

Abstract

In the non-reciprocal Su-Schrieffer-Heeger (SSH) chain, the hopping amplitude of an electron in the intra-cell depends on its hopping direction. Consequently, the non-Hermitian SSH chain has both non-trivial topological edge states and non-Hermitian skin effect. However, how to detect the non-trivial topological edge states and non-Hermitian skin effect have become an important topics in non-Hermitian physics. In this paper, we have studied the dependences of the non-trivial topological edge states and the non-Hermitian skin effect of non-Hermitian SSH chain on their electron transport properties in the vicinity of the zero energy. It is demonstrated that when the peak value of the electron transmission probability in the vicinity of the zero energy is much smaller than 1, the non-Hermitian SSH chain has a left-non-Hermitian skin effect; while that in the vicinity of the zero energy is much larger than 1, the non-Hermitian SSH chain has a right-non-Hermitian skin effect. In particular, the skin effect of non-Hermitian SSH chain can be further enhanced in the region of non-trivial topological edge states. Moreover, with increasing the electron tunneling coupling amplitudes between the non-Hermitian SSH chain and the left and right leads from the weak coupling regime to the strong coupling one, the number of the dips of reflection probability in the vicinity of the zero energy will change from two to zero. Therefore, these results theoretically provide an alternative scheme for detecting non-trivial topological edge states and non-Hermitian skin effect types of the non-Hermitian SSH chain.