Vidya Madhavan, University of Illinois Urbana-Champaign, Signatures of Dispersing Majorana Modes in a Proximitized Topological Material
Speaker
Vidya Madhavan
Physics
University of Illinois Urbana-Champaign
Bio
Professor Madhavan received her bachelor's degree in metallurgical engineering in 1991 from the Indian Institute of Technology, Chennai, and a master of technology degree in solid state materials in 1993 from the Indian Institute of Technology, New Delhi. She completed her phD in 2000 from Boston University. She held a postdoctoral appointment at the University of California, Berkeley from 1999 to 2002, before joining the physics faculty at Boston College in 2002. She joined the faculty at Illinois in 2014 as a full professor.
Abstract
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 the first realization of dispersing Majorana states in 1D.
