Proximity and gating effects of a topological insulator and an s-wave superconductor in Bi2Se3-NbN thin film bilayers

Speaker
Gad Koren, Technion
Date
21/05/2015 - 16:30 - 15:30Add to Calendar 2015-05-21 15:30:00 2015-05-21 16:30:00 Proximity and gating effects of a topological insulator and an s-wave superconductor in Bi2Se3-NbN thin film bilayers In recent years we have been involved in the search for Majorana fermions (MF) in topological superconducting thin films [1-3]. The idea was to induce superconductivity in the doped topological insulator Bi2Se3 by the proximity effect when it is sandwiched in a bilayer with an s-wave superconductor. For this we deposited bilayer thin films of Bi2Se3-NbN from which we prepared junctions of Bi2Se3-NbN-Au. Conductance spectra results of these junctions showed robust zero bias conductance peaks, which indicate unconventional superconductivity, but did not provide a conclusive evidence for MF. In the past year we investigated ultra-thin bilayers of Bi2Se3-NbN, and compared their properties to those of bare NbN reference films of the same thickness [4]. In my talk I shall discuss some of our recent results, in particular, gating effects of these bilayers, where significant magnetoresistance structures are observed also above the superconducting transition temperature.   [1]  G. Koren, T. Kirzhner, E. Lahoud, K. B. Chashka, and A. Kanigel, Phys. Rev. B 84, 224521 (2011).                                                                                                                     [2] G. Koren and T. Kirzhner, Phys. Rev. B 86, 144508 (2012).  [3] Gad Koren, Tal Kirzhner, YoavKalcheim and Oded Millo, EPL 103, 67010, (2013). [4] Gad Koren, Supercond. Sci. Technol. 28, 025003 (2015). Resnick Building 209, room 210 המחלקה לפיזיקה physics.dept@mail.biu.ac.il Asia/Jerusalem public
Place
Resnick Building 209, room 210
Abstract

In recent years we have been involved in the search for Majorana fermions (MF) in topological superconducting thin films [1-3]. The idea was to induce superconductivity in the doped topological insulator Bi2Se3 by the proximity effect when it is sandwiched in a bilayer with an s-wave superconductor. For this we deposited bilayer thin films of Bi2Se3-NbN from which we prepared junctions of Bi2Se3-NbN-Au. Conductance spectra results of these junctions showed robust zero bias conductance peaks, which indicate unconventional superconductivity, but did not provide a conclusive evidence for MF. In the past year we investigated ultra-thin bilayers of Bi2Se3-NbN, and compared their properties to those of bare NbN reference films of the same thickness [4]. In my talk I shall discuss some of our recent results, in particular, gating effects of these bilayers, where significant magnetoresistance structures are observed also above the superconducting transition temperature.  

[1]  G. Koren, T. Kirzhner, E. Lahoud, K. B. Chashka, and A. Kanigel, Phys. Rev. B 84, 224521 (2011).                                                                                                                    

[2] G. Koren and T. Kirzhner, Phys. Rev. B 86, 144508 (2012). 

[3] Gad Koren, Tal Kirzhner, YoavKalcheim and Oded Millo, EPL 103, 67010, (2013).

[4] Gad Koren, Supercond. Sci. Technol. 28, 025003 (2015).

תאריך עדכון אחרון : 03/03/2015