Nearly quantized conductance plateau of vortex zero mode in an iron-based superconductor

Shiyu Zhu; Lingyuan Kong; Lu Cao; Hui Chen; Michał Papaj; Shixuan Du; Yuqing Xing; Wenyao Liu; Dongfei Wang; Chengmin Shen; Fazhi Yang; John Schneeloch; Ruidan Zhong; Genda Gu; Liang Fu; Yu-Yang Zhang; Hong Ding; Hong-Jun Gao

doi:10.1126/science.aax0274

Nearly quantized conductance plateau of vortex zero mode in an iron-based superconductor

Science. 2020 Jan 10;367(6474):189-192. doi: 10.1126/science.aax0274. Epub 2019 Dec 12.

Authors

Shiyu Zhu^#^{1

2}, Lingyuan Kong^#^{1

2}, Lu Cao^#^{1

2}, Hui Chen^#^{1

2}, Michał Papaj³, Shixuan Du^{1

2

4

5}, Yuqing Xing^{1

2}, Wenyao Liu^{1

2}, Dongfei Wang^{1

2}, Chengmin Shen^{1

4}, Fazhi Yang^{1

2}, John Schneeloch⁶, Ruidan Zhong⁶, Genda Gu⁶, Liang Fu³, Yu-Yang Zhang^{7

1

4}, Hong Ding^{8

2

4

5}, Hong-Jun Gao^{8

2

4

5}

Affiliations

¹ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
² School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
³ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
⁴ CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China.
⁵ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China.
⁶ Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
⁷ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China. hjgao@iphy.ac.cn dingh@iphy.ac.cn zhangyuyang@ucas.ac.cn.
⁸ Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. hjgao@iphy.ac.cn dingh@iphy.ac.cn zhangyuyang@ucas.ac.cn.

^# Contributed equally.

PMID: 31831637
DOI: 10.1126/science.aax0274

Abstract

Majorana zero modes (MZMs) are spatially localized, zero-energy fractional quasiparticles with non-Abelian braiding statistics that hold promise for topological quantum computing. Owing to the particle-antiparticle equivalence, MZMs exhibit quantized conductance at low temperature. By using variable-tunnel-coupled scanning tunneling spectroscopy, we studied tunneling conductance of vortex bound states on FeTe_0.55Se_0.45 superconductors. We report observations of conductance plateaus as a function of tunnel coupling for zero-energy vortex bound states with values close to or even reaching the 2e ²/h quantum conductance (where e is the electron charge and h is Planck's constant). By contrast, no plateaus were observed on either finite energy vortex bound states or in the continuum of electronic states outside the superconducting gap. This behavior of the zero-mode conductance supports the existence of MZMs in FeTe_0.55Se_0.45.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.