Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Focus Session: Chiral Topological Superconductors and Majorana Fermions
TT 32.7: Vortrag
Dienstag, 13. März 2018, 12:30–12:45, H 0104
Search for topological superconductivity in the proximitized, quantum-spin-Hall edge state of bismuth bilayers — •Berthold Jaeck1, Yonglong Xie1, Sangjun Jeon1, Aris Alexandradinata2, B. Andrei Bernevig1, and Ali Yazdani1 — 1Department of Physics, Princeton University, Princeton, NJ 08544, USA — 2Department of Physics, Yale University, New Haven, CT 06520, USA
Two-dimensional topological insulators host helical, one-dimensional (1D) modes that are protected by time-reversal symmetry. Proximity induced superconductivity on such edge modes is predicted to be topological in nature and provide a platform for realization of Majorana zero modes. Previously, scanning tunneling microscopy (STM) studies have found evidence for topological edge modes in bismuth (Bi) bilayers on the surface of bulk Bi(111) (1). By epitaxially growing thin films on the surface of Nb, we have successfully induced superconductivity into (111) oriented Bi films. Using high-resolution STM spectroscopy and quasi-particle interference mapping, we characterize the nature of both the normal and the superconducting properties of Bi bilayer edge modes. We find the 1D edge mode to develop a hard superconducting gap that appears to be spectroscopically distinct from the 2D surface gap of the bilayer islands. We will describe these and other experiments designed to elucidate the nature of superconductivity and search for signatures of topological superconductivity in these 1D topological edge states.
I. Drozdov et al., Nature Phys. 10 (2014) 664.