Majorana bound state observed in Fe-based superconductors

Iron-base superconductor (FeSC) is nontrivial on both topological band structure and exotic quasiparticle excitations. Recently, Majorana bound state (MBS) was observed as non-split zero-bias conductance peak across a vortex core of Fe(Te, Se). Due to a small Fermi energy, a large energy gap separates the MBS with other trivial bound states, which makes FeSC a promising high-T_c platform for advance study of MBS and topological quantum qubit. In this talk, I will focus on the properties of MBS shown in our STM experiments. We found the observed MBS is most probably contributed by surface “Dirac fermions”. The “unavoidable” bulk of Fe(Te, Se) plays as quasiparticle bath, which destroys MBS in a lifting temperature. I will also discuss some new Majorana evidences of FeSC identified in recent tunneling experiments.

Reference
[1] P. Zhang et al., Science 360, 182 (2018).
[2] D.-F. Wang*, L.-Y. Kong*, P. Fan* et al., Science 362, 333 (2018).

*In collaboration with H. Ding, H.-J. Gao, S.-X. Du, Y.-J. Sun, D.-F. Wang, S.-Y. Zhu, P. Fan, L. Cao, H. Chen, W.-Y. Liu (IOP, CAS). L. Fu, M. Papaj, H. Isobe (MIT). G.-D. Gu, J. Schneeloch, R.-D. Zhong (BNL).