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

Reaching a conductance plateau The surface of the iron-based superconductor FeTe 0.55 Se 0.45 satisfies the necessary conditions to support topological superconductivity. Under the application of a magnetic field, vortices with zero-bias peaks that are consistent with Majorana bound states have been observed. Using scanning tunneling spectroscopy, Zhu et al. studied the conductance of these states as the tip-sample distance was reduced (see the Perspective by Sau). The researchers found that the value of the conductance increased and eventually saturated. For one of the vortices they studied, the conductance reached a quantized value that is characteristic of the Majorana bound states. Science , this issue p. 189 ; see also p. 145