Journal Article

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

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

2020

Overview

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 FeTe0.55Se0.45 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 2e²/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 FeTe0.55Se0.45.

• Publisher: American Association for the Advancement of Science,The American Association for the Advancement of Science
• Subject: Braiding / Conductance / Electron states / Elementary excitations / Iron / Low temperature / Magnetic fields / Plateaus / Quantum computing / Scanning tunneling microscopy / Spectroscopic analysis / Spectroscopy / Spectrum analysis / Superconductivity / Superconductors / Topology / Vortices