Majorana zero-energy bound states have been proposed to exist at the ends of one-dimensional Rashba nanowires proximity-coupled to an s-wave superconductor in an external magnetic field1,2. Such hybrid structures are a central platform in the search for non-Abelian Majorana zero modes that may be applied in fault-tolerant topological quantum computing3,4. Here we report the discovery of zero-energy bound states simultaneously appearing at both ends of a one-dimensional atomic line defect in monolayer iron-based high-temperature superconductor FeTe0.5Se0.5 films. The spectroscopic properties of the zero-energy bound states, including the temperature and tunnelling barrier dependences, as well as their fusion induced by coupling on line defects of different lengths are found to be robust and consistent with those of the Majorana zero modes. These observations suggest a realization of topological Shockley defects at the ends of an atomic line defect in a two-dimensional s-wave superconductor that can host a Kramers pair of Majorana zero modes protected by time-reversal symmetry along the chain. Our findings reveal a class of topological line defect excitations in two-dimensional superconductor FeTe0.5Se0.5 monolayer films and offer an advantageous platform for generating topological zero-energy excitations at higher operating temperatures, in a single material, and under zero external magnetic field.
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This work was supported by the National Natural Science Foundation of China (no. 11888101), the National Key Research and Development Program of China (2018YFA0305604 and 2017YFA0303302), the National Natural Science Foundation of China (no. 11774008), the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB28000000), the Beijing Natural Science Foundation (Z180010) and the US Department of Energy, Basic Energy Sciences (grant no. DE-FG02–99ER45747: K.J. and Z.W.).
The authors declare no competing interests.
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Chen, C., Jiang, K., Zhang, Y. et al. Atomic line defects and zero-energy end states in monolayer Fe(Te,Se) high-temperature superconductors. Nat. Phys. 16, 536–540 (2020). https://doi.org/10.1038/s41567-020-0813-0
Science Bulletin (2020)