Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 70: Special Session: Topology

FM 70.4: Invited Talk

Donnerstag, 26. September 2019, 12:30–13:00, Audi Max

Status of the search for Majorana zero modes in semiconductor nanowires — •Sergey Frolov — University of Pittsburgh

Majorana modes are non-trivial quantum excitations that have remarkable topological properties and can be used to protect quantum information against decoherence. Tunneling spectroscopy measurements on one-dimensional superconducting hybrid materials have revealed signatures of Majorana zero modes which are the edge states of a bulk topological superconducting phase. We couple strong spin-orbit semiconductor InSb nanowires to conventional superconductors (NbTiN, Al) to obtain additional signatures of Majorana modes and to explore the topological phase transition. A potent alternative explanation for many of the recent experimental Majorana reports is that a non-topological Andreev state localizes near the end of a nanowire. We compare Andreev and Majorana modes and investigate ways to clearly distinguish the two phenomena. We explore new materials combinations in the broad superconductor-semiconductor family to find a perfect pair for the realization of topological quantum bits. I will present our progress towards assembling the apparatus for the future Majorana fusion and braiding experiments.