Abstract
A topological superconductor (TSC) is characterized by the topologically protected gapless surface state that is essentially an Andreev bound state consisting of Majorana fermions. While a TSC has not yet been discovered, the doped topological insulator , which superconducts below , has been predicted to possess a topological superconducting state. We report that the point-contact spectra on the cleaved surface of superconducting present a zero-bias conductance peak (ZBCP) which signifies unconventional superconductivity. Theoretical considerations of all possible superconducting states help us conclude that this ZBCP is due to Majorana fermions and gives evidence for a topological superconductivity in . In addition, we found an unusual pseudogap that develops below and coexists with the topological superconducting state.
- Received 2 August 2011
DOI:https://doi.org/10.1103/PhysRevLett.107.217001
© 2011 American Physical Society