Overview
- Nominated as an outstanding PhD thesis by Boston University, the author was also the recipient of the Gertrude and Maurice Goldhaber Award for Excellence in Physics Research
- Describes the first calculation of phonon mode-specific Dirac fermion coupling ??(q) from experimental data, underscoring the strong coupling between optical surface phonons and surface Dirac fermions in topological insulators
- Presents calculation of the DF spectral function and density of states, allowing for comparison with photoemission and scanning tunneling spectroscopies
- Includes supplementary material: sn.pub/extras
Part of the book series: Springer Theses (Springer Theses)
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Table of contents (8 chapters)
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Front Matter
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Back Matter
Keywords
About this book
The thesis presents experimental and theoretical results about the surface dynamics and the surface Dirac fermion (DF) spectral function of the strong topological insulators Bi2Te3 and Bi2Se3. The experimental results reveal the presence of a strong Kohn anomaly in the measured surface phonon dispersion of a low-lying optical mode, and the absence of surface Rayleigh acoustic phonons. Fitting the experimental data to theoretical models employing phonon Matsubara functions allowed the extraction of the matrix elements of the coupling Hamiltonian and the modifications to the surface phonon propagator that are encoded in the phonon self-energy. This allowed, for the first time, calculation of phonon mode-specific DF coupling λν(q) from experimental data, with average coupling significantly higher than typical values for metals, underscoring the strong coupling between optical surface phonons and surface DFs in topological insulators. Finally, to connect to experimental results obtained from photoemission spectroscopies, an electronic (DF) Matsubara function was constructed using the determined electron-phonon matrix elements and the optical phonon dispersion. This allowed calculation of the DF spectral function and density of states, allowing for comparison with photoemission and scanning tunneling spectroscopies. The results set the necessary energy resolution and extraction methodology for calculating λ from the DF perspective.
Authors and Affiliations
About the author
Dr Colin Howard was awarded a PhD from Boston University in 2015. In 2012 he received the Gertrude and Maurice Goldhaber Award for Excellence in Physics Research, awarded annually to a single graduate student at Boston University for making exceptional contributions to research in their first year of graduate study.
Bibliographic Information
Book Title: Measuring, Interpreting and Translating Electron Quasiparticle - Phonon Interactions on the Surfaces of the Topological Insulators Bismuth Selenide and Bismuth Telluride
Authors: Colin Howard
Series Title: Springer Theses
DOI: https://doi.org/10.1007/978-3-319-44723-0
Publisher: Springer Cham
eBook Packages: Physics and Astronomy, Physics and Astronomy (R0)
Copyright Information: Springer International Publishing Switzerland 2016
Hardcover ISBN: 978-3-319-44722-3Published: 24 October 2016
Softcover ISBN: 978-3-319-83120-6Published: 28 June 2018
eBook ISBN: 978-3-319-44723-0Published: 14 October 2016
Series ISSN: 2190-5053
Series E-ISSN: 2190-5061
Edition Number: 1
Number of Pages: XV, 88
Number of Illustrations: 8 b/w illustrations, 33 illustrations in colour
Topics: Surface and Interface Science, Thin Films, Surfaces and Interfaces, Thin Films, Optics, Lasers, Photonics, Optical Devices, Spectroscopy and Microscopy