| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
|
|
|
|
Observation of Zero-Energy Modes with Possible Time-Reversal Symmetry Breaking on Step Edge of CaKFe$_{4}$As$_{4}$ |
| Lu Cao1,2†, Geng Li1,2,3†, Wenyao Liu1,2,3†, Ya-Bin Liu4, Hui Chen1,2, Yuqing Xing1,2, Lingyuan Kong1,2, Fazhi Yang1,2,3, Quanxin Hu1,2,3, Meng Li1,2, Xingtai Zhou1,2, Zichao Chen1,2, Chenhang Ke5, Lunhui Hu4, Guang-Han Cao4, Congjun Wu5,6,7,8, Hong Ding9,1,3*, and Hong-Jun Gao1,2,3* |
1Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
2School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
3Hefei National Laboratory, Hefei 230088, China
4Department of Physics, Zhejiang University, Hangzhou 310027, China
5New Cornerstone Science Laboratory, Department of Physics, School of Science, Westlake University, Hangzhou 310024, China
6Institute for Theoretical Sciences, Westlake University, Hangzhou 310024, China
7Key Laboratory for Quantum Materials of Zhejiang Province, School of Science, Westlake University, Hangzhou 310024, China
8Institute of Natural Sciences, Westlake Institute for Advanced Study, Hangzhou 310024, China
9Tsung-Dao Lee Institute, and New Cornerstone Science Laboratory, Shanghai Jiao Tong University, Shanghai 201210, China
|
|
| Cite this article: |
|
Lu Cao, Geng Li, Wenyao Liu et al 2024 Chin. Phys. Lett. 41 117401 |
|
|
|
|
Abstract Topologically nontrivial Fe-based superconductors attract extensive attentions due to their ability of hosting Majorana zero modes (MZMs) which could be used for topological quantum computation. Topological defects such as vortex lines are required to generate MZMs. Here, we observe the robust edge states along the surface steps of CaKFe$_{4}$As$_{4}$. Remarkably, the tunneling spectra show a sharp zero-bias peak (ZBP) with multiple integer-quantized states at the step edge under zero magnetic field. We propose that the increasing hole doping around step edges may drive the local superconductivity into a state with possible spontaneous time-reversal symmetry breaking. Consequently, the ZBP can be interpreted as an MZM in an effective vortex in the superconducting topological surface state by proximity to the center of a tri-junction with different superconducting order parameters. Our results provide new insights into the interplay between topology and unconventional superconductivity, and pave a new path to generate MZMs without magnetic field.
|
|
Received: 28 August 2024
Express Letter
Published: 08 October 2024
|
|
| PACS: |
74.25.-q
|
(Properties of superconductors)
|
| |
07.79.Cz
|
(Scanning tunneling microscopes)
|
|
|
|
|
|
| [1] | Paglione J and Greene R L 2010 Nat. Phys. 6 645 |
| [2] | Stewart G R 2011 Rev. Mod. Phys. 83 1589 |
| [3] | Si Q, Yu R, and Abrahams E 2016 Nat. Rev. Mater. 1 16017 |
| [4] | Fernandes R M, Coldea A I, Ding H, Fisher I R, Hirschfeld P J, and Kotliar G 2022 Nature 601 35 |
| [5] | Zhang P, Yaji K, Hashimoto T, Ota Y, Kondo T, Okazaki K, Wang Z J, Wen J S, Gu G D, Ding H, and Shin S 2018 Science 360 182 |
| [6] | Liu Q, Chen C, Zhang T, Peng R, Yan Y J, Wen C H P, Lou X, Huang Y L, Tian J P, Dong X L, Wang G W, Bao W C, Wang Q H, Yin Z P, Zhao Z X, and Feng D L 2018 Phys. Rev. X 8 041056 |
| [7] | Liu W, Cao L, Zhu S, Kong L, Wang G, Papaj M, Zhang P, Liu Y B, Chen H, Li G, Yang F, Kondo T, Du S, Cao G H, Shin S, Fu L, Yin Z, Gao H J, and Ding H 2020 Nat. Commun. 11 5688 |
| [8] | Zhang P, Wang Z, Wu X, Yaji K, Ishida Y, Kohama Y, Dai G, Sun Y, Bareille C, Kuroda K, Kondo T, Okazaki K, Kindo K, Wang X, Jin C, Hu J, Thomale R, Sumida K, Wu S, Miyamoto K, Okuda T, Ding H, Gu G D, Tamegai T, Kawakami T, Sato M, and Shin S 2019 Nat. Phys. 15 41 |
| [9] | Kong L, Cao L, Zhu S, Papaj M, Dai G, Li G, Fan P, Liu W, Yang F, Wang X, Du S, Jin C, Fu L, Gao H J, and Ding H 2021 Nat. Commun. 12 4146 |
| [10] | Cao L, Liu W, Li G, Dai G, Zheng Q, Wang Y, Jiang K, Zhu S, Huang L, Kong L, Yang F, Wang X, Zhou W, Lin X, Hu J, Jin C, Ding H, and Gao H J 2021 Nat. Commun. 12 6312 |
| [11] | Li M, Li G, Cao L, Zhou X, Wang X, Jin C, Chiu C K, Pennycook S J, Wang Z, and Gao H J 2022 Nature 606 890 |
| [12] | Liu W, Hu Q, Wang X, Zhong Y, Yang F, Kong L, Cao L, Li G, Peng Y, Okazaki K, Kondo T, Jin C, Xu J, Gao H J, and Ding H 2022 Quantum Front. 1 20 |
| [13] | Kallin C and Berlinsky J 2016 Rep. Prog. Phys. 79 054502 |
| [14] | 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 Science 362 333 |
| [15] | Kong L, Zhu S, Papaj M, Chen H, Cao L, Isobe H, Xing Y, Liu W, Wang D, Fan P, Sun Y, Du S, Schneeloch J, Zhong R, Gu G, Fu L, Gao H J, and Ding H 2019 Nat. Phys. 15 1181 |
| [16] | Machida T, Sun Y, Pyon S, Takeda S, Kohsaka Y, Hanaguri T, Sasagawa T, and Tamegai T 2019 Nat. Mater. 18 811 |
| [17] | Zhu S Y, Kong L Y, Cao L, Chen H, Papaj M, Du S X, Xing Y Q, Liu W Y, Wang D F, Shen C M, Yang F Z, Schneeloch J, Zhong R D, Gu G D, Fu L, Zhang Y Y, Ding H, and Gao H J 2020 Science 367 189 |
| [18] | Wang Z Y, Rodriguez J O, Jiao L, Howard S, Graham M, Gu G D, Hughes T L, Morr D K, and Madhavan V 2020 Science 367 104 |
| [19] | Iyo A, Kawashima K, Kinjo T, Nishio T, Ishida S, Fujihisa H, Gotoh Y, Kihou K, Eisaki H, and Yoshida Y 2016 J. Am. Chem. Soc. 138 3410 |
| [20] | Chen C, Jiang K, Zhang Y, Liu C F, Liu Y, Wang Z Q, and Wang J 2020 Nat. Phys. 16 536 |
| [21] | Fente A, Meier W R, Kong T, Kogan V G, Bud'ko S L, Canfield P C, Guillamón I, and Suderow H 2018 Phys. Rev. B 97 134501 |
| [22] | Fang D, Shi X, Du Z, Richard P, Yang H, Wu X X, Zhang P, Qian T, Ding X, Wang Z, Kim T K, Hoesch M, Wang A, Chen X, Hu J, Ding H, and Wen H H 2015 Phys. Rev. B 92 144513 |
| [23] | Hanaguri T, Niitaka S, Kuroki K, and Takagi H 2010 Science 328 474 |
| [24] | Misra S, Oh S, Hornbaker D J, DiLuccio T, Eckstein J N, and Yazdani A 2002 Phys. Rev. B 66 100510 |
| [25] | Shan L, Wang Y L, Shen B, Zeng B, Huang Y, Li A, Wang D, Yang H, Ren C, Wang Q H, Pan S H, and Wen H H 2011 Nat. Phys. 7 325 |
| [26] | Liu X, Tao R, Ren M, Chen W, Yao Q, Wolf T, Yan Y, Zhang T, and Feng D 2019 Nat. Commun. 10 1039 |
| [27] | Jäck B, Xie Y, and Yazdani A 2021 Nat. Rev. Phys. 3 541 |
| [28] | Cao L, Song Y, Liu Y B, Zheng Q, Han G, Liu W, Li M, Chen H, Xing Y, Cao G H, Ding H, Lin X, Du S, Zhang Y Y, Li G, Wang Z, and Gao H J 2021 Nano Res. 14 3921 |
| [29] | Farinacci L, Ahmadi G, Reecht G, Ruby M, Bogdanoff N, Peters O, Heinrich B W, von Oppen F, and Franke K J 2018 Phys. Rev. Lett. 121 196803 |
| [30] | Lee W C, Zhang S C, and Wu C 2009 Phys. Rev. Lett. 102 217002 |
| [31] | Maiti S and Chubukov A V 2013 Phys. Rev. B 87 144511 |
| [32] | Grinenko V, Materne P, Sarkar R, Luetkens H, Kihou K, Lee C H, Akhmadaliev S, Efremov D V, Drechsler S L, and Klauss H H 2017 Phys. Rev. B 95 214511 |
| [33] | Grinenko V, Sarkar R, Kihou K, Lee C H, Morozov I, Aswartham S, Büchner B, Chekhonin P, Skrotzki W, Nenkov K, Hühne R, Nielsch K, Drechsler S L, Vadimov V L, Silaev M A, Volkov P A, Eremin I, Luetkens H, and Klauss H H 2020 Nat. Phys. 16 789 |
| [34] | Iguchi Y, Shi R A, Kihou K, Lee C H, Barkman M, Benfenati A L, Grinenko V, Babaev E, and Moler K A 2023 Science 380 1244 |
| [35] | Zhao S Z, Song H Y, Hu L L, Xie T, Liu C, Luo H Q, Jiang C Y, Zhang X, Nie X C, Meng J Q, Duan Y X, Liu S B, Xie H Y, and Liu H Y 2020 Phys. Rev. B 102 144519 |
| [36] | Bobkov A M and Bobkova I V 2011 Phys. Rev. B 84 134527 |
| [37] | Benfenati A and Babaev E 2022 Phys. Rev. B 105 134518 |
| [38] | Fu L and Kane C L 2008 Phys. Rev. Lett. 100 096407 |
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
