Observation of robust zero-energy state and enhanced superconducting gap in a trilayer heterostructure of MnTe/Bi <sub>2</sub> Te <sub>3</sub> /Fe(Te, Se)
Shuyue Ding, Chen Chen, Zhipeng Cao, Di Wang, Yongqiang Pan, Ran Tao, Dongming Zhao, Yining Hu, Tianxing Jiang, Y. J. Yan, Zhixiang Shi, Xiangang Wan, Donglai Feng, Tong Zhang
Abstract
The interface between magnetic material and superconductors has long been predicted to host unconventional superconductivity, such as spin-triplet pairing and topological nontrivial pairing state, particularly when spin-orbital coupling (SOC) is incorporated. To identify these unconventional pairing states, fabricating homogenous heterostructures that contain such various properties are preferred but often challenging. Here, we synthesized a trilayer-type van der Waals heterostructure of MnTe/Bi 2 Te 3 /Fe(Te, Se), which combined s-wave superconductivity, thickness-dependent magnetism, and strong SOC. Via low-temperature scanning tunneling microscopy, we observed robust zero-energy states with notably nontrivial properties and an enhanced superconducting gap size on single unit cell (UC) MnTe surface. In contrast, no zero-energy state was observed on 2-UC MnTe. First-principle calculations further suggest that the 1-UC MnTe has large interfacial Dzyaloshinskii-Moriya interaction and a frustrated AFM state, which could promote noncolinear spin textures. It thus provides a promising platform for exploring topological nontrivial superconductivity.