University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Wednesday, April 10th 2019
1:25 pm:
Speaker: Vidya Madhavan, University of Illinois - Urbana-Champaign
Subject:  Signatures of 1D dispersing Majorana modes in the proximitized topological surface states of FeSe0.5Te0.5

Majorana fermions can be realized as quasiparticle excitations in a topological superconductor, whose non-Abelian statistics provide a route to developing robust qubits. In this context, there has been a recent surge of interest in the iron-based superconductor, FeSe0.5Te0.5. Theoretical calculations have shown that FeSe0.5Te0.5 may have an inverted band structure which may lead to topological surface states, which can in turn host Majorana modes under certain conditions in the superconducting phase. Furthermore, recent STM studies have demonstrated the existence of zero-bias bound states inside vortex cores which have been interpreted as signatures of Majorana modes. While most recent studies have focused on Majorana bound states, more generally, akin to elementary particles, Majorana fermions can propagate and display linear dispersion. These excitations have not yet been directly observed, and can also be used for quantum information processing. This talk is focused on our recent work in realizing dispersing Majorana modes. I will describe the conditions under which such states can be realized in condensed matter systems and what their signatures are. Finally, I will describe our scanning tunneling experiments of domain walls in the superconductor FeSe0.45Te0.55, which might potentially be first realization of dispersing Majorana states in 1D.

Faculty Host: Martin Greven

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