Multiple topological states in iron-based superconductors

Peng Zhang; Zhijun Wang; Xianxin Wu; Koichiro Yaji; Yukiaki Ishida; Yoshimitsu Kohama; Guangyang Dai; Yue Sun; Cedric Bareille; Kenta Kuroda; Takeshi Kondo; Kozo Okazaki; Koichi Kindo; Xiancheng Wang; Changqing Jin; Jiangping Hu; Ronny Thomale; Kazuki Sumida; Shilong Wu; Koji Miyamoto; Taichi Okuda; Hong Ding; G. D. Gu; Tsuyoshi Tamegai; Takuto Kawakami; Masatoshi Sato; Shik Shin

doi:10.1038/s41567-018-0280-z

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arXiv · 1809.09977

Multiple topological states in iron-based superconductors

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Abstract

Topological insulators and semimetals as well as unconventional iron-based superconductors have attracted major recent attention in condensed matter physics. Previously, however, little overlap has been identified between these two vibrant fields, even though the principal combination of topological bands and superconductivity promises exotic unprecedented avenues of superconducting states and Majorana bound states (MBSs), the central building block for topological quantum computation. Along with progressing laser-based spin-resolved and angle-resolved photoemission spectroscopy (ARPES) towards high energy and momentum resolution, we have resolved topological insulator (TI) and topological Dirac semimetal (TDS) bands near the Fermi level ($E_{\text{F}}$) in the iron-based superconductors Li(Fe,Co)As and Fe(Te,Se), respectively. The TI and TDS bands can be individually tuned to locate close to $E_{\text{F}}$ by carrier doping, allowing to potentially access a plethora of different superconducting topological states in the same material. Our results reveal the generic coexistence of superconductivity and multiple topological states in iron-based superconductors, rendering these materials a promising platform for high-$T_{\text{c}}$ topological superconductivity.

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Peng Zhang, Zhijun Wang, Xianxin Wu, Koichiro Yaji, Yukiaki Ishida, Yoshimitsu Kohama, Guangyang Dai, Yue Sun, Cedric Bareille, Kenta Kuroda, Takeshi Kondo, Kozo Okazaki, Koichi Kindo, Xiancheng Wang, Changqing Jin, Jiangping Hu, Ronny Thomale, Kazuki Sumida, Shilong Wu, Koji Miyamoto, Taichi Okuda, Hong Ding, G. D. Gu, Tsuyoshi Tamegai, Takuto Kawakami, Masatoshi Sato, Shik Shin. 2018-09-25. Multiple topological states in iron-based superconductors. https://doi.org/10.1038/s41567-018-0280-z

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