University of Illinois Urbana-Champaign

The superconducting proximity effect in Bi2Se3 thin-films

Mulcahy, Brian T

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MULCAHY-DISSERTATION-2015.pdf

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https://hdl.handle.net/2142/78336

Description

Title
The superconducting proximity effect in Bi2Se3 thin-films
Author(s)
Mulcahy, Brian T
Issue Date
2015-03-19
Director of Research (if dissertation) or Advisor (if thesis)
Eckstein, James N.
Doctoral Committee Chair(s)
MacDougall, Gregory
Committee Member(s)
  • Thaler, Jon
  • Hughes, Taylor
Department of Study
Physics
Discipline
Physics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Date of Ingest
2015-07-22T22:16:14Z
Keyword(s)
  • Bismuth selenide (Bi2Se3)
  • Topological insulator
  • Molecular beam epitaxy
  • Josephson junction
  • Josephson junction array
  • Majorana fermion
  • Transport
Abstract
States of matter distinguished by the topology of their bands rather than any broken symmetry represent a vast, largely unexplored realm of condensed matter physics. Such states, realized in condensed matter systems, support exotic excitations that obey rules distinct from fermions and bosons. They are of basic interest, illustrating Nature’s limitless creativity, and practical in-terest in that they may prove ideal platforms for the construction of error-proof quantum com-putational devices. In this work, the topological insulator Bi2Se3, which supports special metallic surface states as a consequence of the topology of its bulk bands, is tiled with micron-scale islands of the superconductor niobium. The superconducting islands interact with the Bi2Se3 and each other through the superconducting proximity effect and the Josephson effect. Theoretical work asserts that this system supports so-called Majorana bound states, which are exotic excitations that possess some of the features necessary to construct a topologically protected quantum bit. Transport studies on these topological Josephson array devices show that the presence of the islands leads to correlated transport and vortex dynamics in the topological insulator wire. These devices may serve as an ideal platform for further investigation into Majorana physics and other manifestations of the topological nature of the Bi2Se3 wires.
Graduation Semester
2015-5
Type of Resource
text
Permalink
http://hdl.handle.net/2142/78336
Copyright and License Information
Copyright 2015 Brian T. Mulcahy

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