Field-free platform for topological zero-energy mode in superconductors LiFeAs and PbTaSe$_2$

Songtian S. Zhang; Jia-Xin Yin; Guangyang Dai; Lingxiao Zhao; Tay-Rong Chang; Nana Shumiya; Kun Jiang; Hao Zheng; Guang Bian; Daniel Multer; Maksim Litskevich; Guoqing Chang; Ilya Belopolski; Tyler A. Cochran; Xianxin Wu; Desheng Wu; Jianlin Luo; Genfu Chen; Hsin Lin; Fang-Cheng Chou; Xiancheng Wang; Changqing Jin; Raman Sankar; Ziqiang Wang; M. Zahid Hasan

doi:10.1103/physrevb.101.100507

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arXiv · 1912.11513

Field-free platform for topological zero-energy mode in superconductors LiFeAs and PbTaSe$_2$

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Abstract

Superconducting materials exhibiting topological properties are emerging as an exciting platform to realize fundamentally new excitations from topological quantum states of matter. In this work, we explore the possibility of a field-free platform for generating Majorana zero energy excitations by depositing magnetic Fe impurities on the surface of candidate topological superconductors, LiFeAs and PbTaSe$_2$. We use scanning tunneling microscopy to probe localized states induced at the Fe adatoms on the atomic scale and at sub-Kelvin temperatures. We find that each Fe adatom generates a striking zero-energy bound state inside the superconducting gap, which do not split in magnetic fields up to 8T, underlining a nontrivial topological origin. Our findings point to magnetic Fe adatoms evaporated on bulk superconductors with topological surface states as a new platform for exploring Majorana zero modes and quantum information science under field-free conditions.

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Songtian S. Zhang, Jia-Xin Yin, Guangyang Dai, Lingxiao Zhao, Tay-Rong Chang, Nana Shumiya, Kun Jiang, Hao Zheng, Guang Bian, Daniel Multer, Maksim Litskevich, Guoqing Chang, Ilya Belopolski, Tyler A. Cochran, Xianxin Wu, Desheng Wu, Jianlin Luo, Genfu Chen, Hsin Lin, Fang-Cheng Chou, Xiancheng Wang, Changqing Jin, Raman Sankar, Ziqiang Wang, M. Zahid Hasan. 2019-12-24. Field-free platform for topological zero-energy mode in superconductors LiFeAs and PbTaSe$_2$. https://doi.org/10.1103/physrevb.101.100507

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