Next Seminar (online)

Host and guests in proximity effect: a story of superconducting hybrid systems

Wednesday May 19th 2021, 14h30h – Online

Invited speaker:
Sambit Mohapatra

(Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg)

 A hybrid material system is composed of at least two materials whose properties are different from each other. Usually, one of the two constituent materials is more or less known and well-studied which can be seen as the host, while the other is relatively less explored as a constituent of the hybrid system and can be considered as the guest. Naturally, the initial scientific attention goes towards the guest material, focusing on exploring its properties when embedded in the hybrid system. Nevertheless, it is also important to recognize the significance of the effect of the presence of the guest on the properties of the host material and how that may affect the properties of the overall hybrid system. In this talk, I will speak about one such guest-host hybrid system; a hybrid superconducting (host)-semiconducting (guest) system.

Hybrid superconducting-semiconducting material systems have been gaining attention after the theoretical proposals of such systems harboring the elusive Majorana fermions, when driven towards topological superconductivity. ,  Especially, a high spin-orbit high g-factor semiconducting nanowire in proximity to an ordinary superconductor can be driven to become topologically superconducting by applying an appropriate magnetic field. The signature of the Majorana fermions is characterized by a robust conductance peak within the superconducting gap at zero bias (called as zero bias conductance peaks or ZBCP). However, such studies have left several important questions unanswered which are crucial for a correct interpretation of the system. 

While most of the attention is on the topological material (e.g. semiconducting nanowire) side, we decided to take a step back and take a closer look at the superconducting side of the hybrid system. To do that, we theoretically model the tunnel conductance through the superconductor only, with the high topological material simply being present in its proximity. We show that such trivial superconducting systems may also exhibit similar ZBCPs due to inverse proximity effect. We also address on how various superconducting depairing mechanisms may play an important role in the emergence of such ZBCPs.

Upcoming seminars

  • Hugues Pothier (TBA)



Past seminars 2020

  • Michael Manfra (Purdue University)

  • Banan Kerdi (LNCMI-Toulouse)

  • Abhishek Juyal (Neel Institute)

  • Arthur Marguerite (College de France)

  • Kamran Behnia (ESPCI)

  • Pierre Capiod (Debye institute for Nanomaterials)

  • Audrey Bienfait (ENS-Lyon)

  • Sebastien Toussain (UCL)

  • David Goldhaber-Gordon (Stanford)

  • Javad Shabani (NYU)

  • Olivier Maillet (Aalto)

  • Mitali Banerjee (EPFL)

  • Anais Dreau (L2C) 

  • Klaus Ensslin (ETH- Zurich) 

  • Xavier Waintal (CEA- Grenoble) 

  • Gwendal Feve (LPENS) 

  • Shuoying Yang (MPI-Halle) 

  • Yann Gallais (MPQ) 

  • Carles Altimiras (CEA - Saclay)

  • Alexandra Palacio- Morales ( LPS) 

  • Everton Arrighi (Neel Institute)