Influence of topological edge states on the properties of Al/Bi2Se3/Al hybrid Josephson devices
Journal article, 2014

In superconductor-topological insulator-superconductor hybrid junctions, the barrier edge states are expected to be protected against backscattering, to generate unconventional proximity effects, and, possibly, to signal the presence of Majorana fermions. The standards of proximity modes for these types of structures have to be settled for a neat identification of possible new entities. Through a systematic and complete set of measurements of the Josephson properties we find evidence of ballistic transport in coplanar Al-Bi2Se3-Al junctions that we attribute to a coherent transport through the topological edge state. The shunting effect of the bulk only influences the normal transport. This behavior, which can be considered to some extent universal, is fairly independent of the specific features of superconducting electrodes. A comparative study of Shubnikov-de Haas oscillations and scanning tunneling spectroscopy gave an experimental signature compatible with a two-dimensional electron transport channel with a Dirac dispersion relation. A reduction of the size of the Bi2Se3 flakes to the nanoscale is an unavoidable step to drive Josephson junctions in the proper regime to detect possible distinctive features of Majorana fermions.

Author

L. Galletti

Sophie Charpentier

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

M. Iavarone

P. Lucignano

D. Massarotti

Riccardo Arpaia

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Y. Suzuki

Kazuo Kadowaki

Thilo Bauch

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

A. Tagliacozzo

F. Tafuri

Floriana Lombardi

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Physical Review B - Condensed Matter and Materials Physics

1098-0121 (ISSN)

Vol. 89

Subject Categories

Condensed Matter Physics

DOI

10.1103/PhysRevB.89.134512