Fe$_{1+y}$Te$_{x}$Se$_{1-x}$: A Delicate and Tunable Majorana Material
Fazhi Yang1,2†, Giao Ngoc Phan1,3†*, Renjie Zhang1,2, Jin Zhao1,2, Jiajun Li1,2, Zouyouwei Lu1,2, John Schneeloch4, Ruidan Zhong4,6, Mingwei Ma1,5, Genda Gu4, Xiaoli Dong1,2,5, Tian Qian1,5, and Hong Ding1,3,6*
1Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2School of Physics, University of Chinese Academy of Sciences, Beijing 100190, China 3CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China 4Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY, USA 5Songshan Lake Materials Laboratory, Dongguan 523808, China 6Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 201210, China
Abstract：We report the observation for the $p_{z}$ electron band and the band inversion in Fe$_{1+y}$Te$_{x}$Se$_{1-x}$ with angle-resolved photoemission spectroscopy. Furthermore, we found that excess Fe ($y> 0$) inhibits the topological band inversion in Fe$_{1+y}$Te$_{x}$Se$_{1-x}$, which explains the absence of Majorana zero modes in previous reports for Fe$_{1+y}$Te$_{x}$Se$_{1-x}$ with excess Fe. Based on our analysis of different amounts of Te doping and excess Fe, we propose a delicate topological phase in this material. Thanks to this delicate phase, one may be able to tune the topological transition via applying lattice strain or carrier doping.
Zhang P, Yaji K, Hashimoto T, Ota Y, Kondo T, Okazaki K, Wang Z J, Wen J S, Gu G D, Ding H, and Shik S 2018 Science360 182
[2]
Wang D F, Kong L Y, Fan P, Chen H, Zhu S Y, Liu W Y, Cao L, Sun Y J, Du S X, Schneeloch J, Zhong R D, Gu G D, Fu L, Ding H, and Gao H J 2018 Science362 333
[3]
Liu W Y, Cao L, Zhu S Y, Kong L Y, Wang G W, Papaj M, Zhang P, Liu Y B, Chen H, Li G, Yang F Z, Kondo T, Du S X, Cao G H, Shin S, Fu L, Yin Z P, Gao H J, and Ding H 2020 Nat. Commun.11 5688
[4]
Fan P, Yang F Z, Qian G J, Chen H, Zhang Y Y, Li G, Huang Z H, Xing Y Q, Kong L Y, Liu W Y, Jiang K, Shen C M, Du S X, Schneeloch J, Zhong R D, Gu G D, Wang Z Q, Ding H, and Gao H J 2021 Nat. Commun.12 1348
[5]
Kong L Y, Cao L, Zhu S Y, Papaj M, Dai G Y, Li G, Fan P, Liu W Y, Yang F Z, Wang X C, Du S X, Jin C Q, Fu L, Gao H J, and Ding H 2021 Nat. Commun.12 4146
[6]
Li M, Li G, Cao L, Zhou X T, Wang X C, Jin C Q, Chiu C K, Pennycook J S, Wang Z Q, and Gao H J 2022 Nature606 890
[7]
Liu W Y, Hu Q X, Wang X C, Zhong Y G, Yang F Z, Kong L Y, Cao L, Li G, Okazaki K, Kondo T, Jin C Q, Zhang F C, Xu J P, Gao H J, and Ding H 2022 Quantum Front1 20
[8]
Wang Z J, Zhang P, Xu G, Zeng L K, Miao H, Xu X Y, Qian T, Weng H M, Richard P, Fedorov A V, Ding H, Dai X, and Fang Z 2015 Phys. Rev. B92 115119
Lohani H, Hazra T, Ribak A, Nitzav Y, Fu H X, Yan B H, Randeria M, and Kanigel A 2020 Phys. Rev. B101 245146
[11]
Peng X L, Li Y, Wu X X, Deng H B, Shi X, Fan W H, Li M, Huang Y B, Qian T, Richard P, Hu J P, Pan S H, Mao H Q, Sun Y J, and Ding H 2019 Phys. Rev. B100 155134
[12]
Machida T, Sun Y, Pyon S, Takeda S, Kohsaka Y, Hanaguri T, Sasagawa T, and Tamegai T 2019 Nat. Mater.18 811
[13]
Chen M Y, Chen X Y, Yang H, Du Z Y, Zhu X Y, Wang E Y, and Wen H H 2018 Nat. Commun.9 970
Kong L Y, Zhu S Y, Papaj M, Chen H, Cao L, Isobe H, Xing Y Q, Liu W Y, Wang D F, Fan P, Sun Y J, Du S X, Schneeloch J, Zhong R D, Gu G D, Fu L, Gao H J, and Ding H 2019 Nat. Phys.15 1181
[17]
Li Y M, Zaki N, Garlea V O, Savici A T, Fobes D, Xu Z J, Camino F, Petrovic C, Gu G D, Johnson P D, Tranquada J M, and Zaliznyak I A 2021 Nat. Mater.20 1221
[18]
Singh U R, White S C, Schmaus S, Tsurkan V, Loidl A, Deisenhofer J, and Wahl P 2013 Phys. Rev. B88 155124
[19]
Yin J X, Wu Z, Wang J H, Ye Z Y, Gong J, Hou X Y, Shan L, Li A, Liang X J, Wu X X, Li J, Ting C S, Wang Z Q, Hu J P, Hor P H, Ding H, and Pan S H 2015 Nat. Phys.11 543
2023, Vol. 40 
