Robust Zero Energy Modes on Superconducting Bismuth Islands Deposited on Fe(Te,Se)

Topological superconductivity is one of the frontier research directions in condensed matter physics. One of the unique elementary excitations in topological superconducting state is the Majorana fermion (mode) which is its own antiparticle and obeys the non-Abelian statistics, and thus useful for constructing the fault-tolerant quantum computation. The evidence for Majorana fermions (mode) in condensed matter is now quickly accumulated. We deposit Bi islands on the iron based superconductors Fe(Te,Se), and find the easily achievable zero energy modes on the tunneling spectra on some Bi islands. The zero energy mode is robust and appears everywhere on the island. Temperature and magnetic field dependence of the zero energy mode are also investigated. We attribute these zero energy modes to the Majorana modes due to the proximity effect induced topological superconductivity on the Bi islands with strong spin-orbit coupling effect.