Bulk contribution to magnetotransport properties of low-defect-density Bi2Te3 topological insulator thin films

Prosper Ngabonziza, Y. Wang, Alexander Brinkman

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Abstract

An important challenge in the field of topological materials is to carefully disentangle the electronic transport contribution of the topological surface states from that of the bulk. For Bi2Te3 topological insulator samples, bulk single crystals and thin films exposed to air during fabrication processes are known to be bulk conducting, with the chemical potential in the bulk conduction band. For Bi2Te3 thin films grown by molecular beam epitaxy, we combine structural characterization (transmission electron microscopy), chemical surface analysis as function of time (x-ray photoelectron spectroscopy) and magnetotransport analysis to understand the low defect density and record high bulk electron mobility once charge is doped into the bulk by surface degradation. Carrier densities and electronic mobilities extracted from the Hall effect and the quantum oscillations are consistent and reveal a large bulk carrier mobility. Because of the cylindrical shape of the bulk Fermi surface, the angle dependence of the bulk magnetoresistance oscillations is two dimensional in nature.
Original languageEnglish
Article number044204
Number of pages7
JournalPhysical Review Materials
Volume2
Issue number4
DOIs
Publication statusPublished - 23 Apr 2018

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Galvanomagnetic effects
Defect density
insulators
Thin films
Fermi surface
Electron mobility
Chemical potential
Carrier mobility
defects
Surface analysis
Hall effect
Surface states
Magnetoresistance
Photoelectron spectroscopy
thin films
Conduction bands
Molecular beam epitaxy
Carrier concentration
oscillations
Single crystals

Cite this

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Bulk contribution to magnetotransport properties of low-defect-density Bi2Te3 topological insulator thin films. / Ngabonziza, Prosper; Wang, Y.; Brinkman, Alexander .

In: Physical Review Materials , Vol. 2, No. 4, 044204, 23.04.2018.

Research output: Contribution to journalArticleAcademicpeer-review

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AB - An important challenge in the field of topological materials is to carefully disentangle the electronic transport contribution of the topological surface states from that of the bulk. For Bi2Te3 topological insulator samples, bulk single crystals and thin films exposed to air during fabrication processes are known to be bulk conducting, with the chemical potential in the bulk conduction band. For Bi2Te3 thin films grown by molecular beam epitaxy, we combine structural characterization (transmission electron microscopy), chemical surface analysis as function of time (x-ray photoelectron spectroscopy) and magnetotransport analysis to understand the low defect density and record high bulk electron mobility once charge is doped into the bulk by surface degradation. Carrier densities and electronic mobilities extracted from the Hall effect and the quantum oscillations are consistent and reveal a large bulk carrier mobility. Because of the cylindrical shape of the bulk Fermi surface, the angle dependence of the bulk magnetoresistance oscillations is two dimensional in nature.

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