Quantum transport theory of 3D time-reversal invariant topological insulators

Dellabetta, Brian

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https://hdl.handle.net/2142/50712 Copy

Description

Title

Quantum transport theory of 3D time-reversal invariant topological insulators

Author(s)

Dellabetta, Brian

Issue Date

2014-09-16

Director of Research (if dissertation) or Advisor (if thesis)

Gilbert, Matthew J.

Doctoral Committee Chair(s)

Gilbert, Matthew J.

Committee Member(s)

• Fradkin, Eduardo H.
• Lyding, Joseph W.
• Ravaioli, Umberto

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Topological Insulators
• Quantum Transport
• Non-Equilibrium Green's Function

Abstract

We consider the potential technological role of a recently predicted and discovered phase of quantum matter - topological insulators (TIs), which are characterized by an insulating bulk and topologically protected, gapless, spin-momentum locked surface modes. Precise engineering of these gapless modes may yield new potential materials for novel electronic devices, but many materials issues and open questions in application remain in the nascent field. The quasiparticle dynamics of TI systems can be elegantly written in terms of a low-energy effective momentum-space Hamiltonian, but analytic methods quickly become intractable in multifarious systems and disordered heterostructures which in general lack translational invariance, as momentum is no longer a good quantum number. Computational methods possess a clear advantage in this regime, for understanding systems in which geometry, contact layout, and disorder play a dominant role. We employ computationally intensive methods to calculate observable, non-equilibrium transport dynamics of real-space topological systems, to propose and identify experimental signatures of topological behavior, and to connect interesting experimental observations to the underlying topological properties in normal, disordered, and superconducting systems. The customizability of these computational methods allows us to determine the salient underlying physics involved in a number of different scenarios, including surface transport corrugated TI channels, the Aharonov-Bohm effect in TI nanowires, supercurrent in TI Josephson junctions, and the superconducting proximity effect and resulting transport in TI-superconductor heterostructures. In doing so, we expand the understanding of quantum and mesoscopic transport in heterostructured TI systems as a first step in exploring their long-term place in novel device applications.

Graduation Semester

2014-08

Permalink

http://hdl.handle.net/2142/50712

Copyright and License Information

Copyright 2014 Brian Jon Dellabetta

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