Zero-energy bound states in the high-temperature superconductors at the two-dimensional limit

Chaofei Liu; Cheng Chen; Xiaoqiang Liu; Ziqiao Wang; Yi Liu; Shusen Ye; Ziqiang Wang; Jiangping Hu; Jian Wang

doi:10.1126/sciadv.aax7547

Zero-energy bound states in the high-temperature superconductors at the two-dimensional limit

Sci Adv. 2020 Mar 25;6(13):eaax7547. doi: 10.1126/sciadv.aax7547. eCollection 2020 Mar.

Authors

Chaofei Liu¹, Cheng Chen¹, Xiaoqiang Liu¹, Ziqiao Wang¹, Yi Liu¹, Shusen Ye¹, Ziqiang Wang², Jiangping Hu^{3

4

5

6}, Jian Wang^{1

5

6

7}

Affiliations

¹ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
² Department of Physics, Boston College, Chestnut Hill, MA 02467, USA.
³ Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁴ Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
⁵ Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
⁶ CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.
⁷ Beijing Academy of Quantum Information Sciences, Beijing 100193, China.

Abstract

Majorana zero modes (MZMs) that obey the non-Abelian statistics have been intensively investigated for potential applications in topological quantum computing. The prevailing signals in tunneling experiments "fingerprinting" the existence of MZMs are the zero-energy bound states (ZEBSs). However, nearly all of the previously reported ZEBSs showing signatures of the MZMs are observed in difficult-to-fabricate heterostructures at very low temperatures and additionally require applied magnetic field. Here, by using in situ scanning tunneling spectroscopy, we detect the ZEBSs upon the interstitial Fe adatoms deposited on two different high-temperature superconducting one-unit-cell iron chalcogenides on SrTiO₃(001). The spectroscopic results resemble the phenomenological characteristics of the MZMs inside the vortex cores of topological superconductors. Our experimental findings may extend the MZM explorations in connate topological superconductors toward an applicable temperature regime and down to the two-dimensional (2D) limit.

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