Increased phase coherence length in a porous topological insulator

Alexander Nguyen; Golrokh Akhgar; David L. Cortie; Abdulhakim Bake; Zeljko Pastuovic; Weiyao Zhao; Chang Liu; Yi Hsun Chen; Kiyonori Suzuki; Michael S. Fuhrer; Dimitrie Culcer; Alexander R. Hamilton; Mark T. Edmonds; Julie Karel

doi:10.1103/PhysRevMaterials.7.064202

Increased phase coherence length in a porous topological insulator

Alexander Nguyen, Golrokh Akhgar, David L. Cortie, Abdulhakim Bake, Zeljko Pastuovic, Weiyao Zhao, Chang Liu, Yi Hsun Chen, Kiyonori Suzuki, Michael S. Fuhrer, Dimitrie Culcer, Alexander R. Hamilton, Mark T. Edmonds, Julie Karel

Research output: Contribution to journal › Article › Research › peer-review

4 Citations (Scopus)

Abstract

The surface area of Bi2Te3 thin films was increased by introducing nanoscale porosity. Temperature dependent resistivity and magnetotransport measurements were conducted both on as-grown and porous samples (23 and 70 nm). The longitudinal resistivity of the porous samples became more metallic, indicating the increased surface area resulted in transport that was more surfacelike. Weak antilocalization was present in all samples, and remarkably the phase coherence length doubled in the porous samples. This increase is likely due to the large Fermi velocity of the Dirac surface states. Our results show that the introduction of nanoporosity does not destroy the topological surface states but rather enhances them, making these nanostructured materials promising for low energy electronics, spintronics and thermoelectrics.

Original language	English
Article number	064202
Number of pages	6
Journal	Physical Review Materials
Volume	7
Issue number	6
DOIs	https://doi.org/10.1103/PhysRevMaterials.7.064202
Publication status	Published - 15 Jun 2023

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title = "Increased phase coherence length in a porous topological insulator",

abstract = "The surface area of Bi2Te3 thin films was increased by introducing nanoscale porosity. Temperature dependent resistivity and magnetotransport measurements were conducted both on as-grown and porous samples (23 and 70 nm). The longitudinal resistivity of the porous samples became more metallic, indicating the increased surface area resulted in transport that was more surfacelike. Weak antilocalization was present in all samples, and remarkably the phase coherence length doubled in the porous samples. This increase is likely due to the large Fermi velocity of the Dirac surface states. Our results show that the introduction of nanoporosity does not destroy the topological surface states but rather enhances them, making these nanostructured materials promising for low energy electronics, spintronics and thermoelectrics.",

author = "Alexander Nguyen and Golrokh Akhgar and Cortie, {David L.} and Abdulhakim Bake and Zeljko Pastuovic and Weiyao Zhao and Chang Liu and Chen, {Yi Hsun} and Kiyonori Suzuki and Fuhrer, {Michael S.} and Dimitrie Culcer and Hamilton, {Alexander R.} and Edmonds, {Mark T.} and Julie Karel",

note = "Funding Information: A.N., G.A., J.K., M.T.E., D.L.C., D.C., A.R.H., and M.S.F. acknowledge the funding support from the Australian Research Council Centre of Excellence in Future Low Energy Electronics Technologies (CE170100039). J.K. acknowledges the support from the Australian Research Council Discovery Projects (DP200102477 and DP220103783). This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF). The ion irradiation of this research was undertaken in Australian Neutron Science and Technology Organisation (ANSTO). We would like to acknowledge Professor S. Prawer and use of his laser cutter facility at the University of Melbourne in making the shadow masks. Publisher Copyright: {\textcopyright} 2023 American Physical Society.",

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doi = "10.1103/PhysRevMaterials.7.064202",

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AU - Nguyen, Alexander

AU - Akhgar, Golrokh

AU - Cortie, David L.

AU - Bake, Abdulhakim

AU - Pastuovic, Zeljko

AU - Zhao, Weiyao

AU - Liu, Chang

AU - Chen, Yi Hsun

AU - Suzuki, Kiyonori

AU - Fuhrer, Michael S.

AU - Culcer, Dimitrie

AU - Hamilton, Alexander R.

AU - Edmonds, Mark T.

AU - Karel, Julie

N1 - Funding Information: A.N., G.A., J.K., M.T.E., D.L.C., D.C., A.R.H., and M.S.F. acknowledge the funding support from the Australian Research Council Centre of Excellence in Future Low Energy Electronics Technologies (CE170100039). J.K. acknowledges the support from the Australian Research Council Discovery Projects (DP200102477 and DP220103783). This work was performed in part at the Melbourne Centre for Nanofabrication (MCN) in the Victorian Node of the Australian National Fabrication Facility (ANFF). The ion irradiation of this research was undertaken in Australian Neutron Science and Technology Organisation (ANSTO). We would like to acknowledge Professor S. Prawer and use of his laser cutter facility at the University of Melbourne in making the shadow masks. Publisher Copyright: © 2023 American Physical Society.

PY - 2023/6/15

Y1 - 2023/6/15

N2 - The surface area of Bi2Te3 thin films was increased by introducing nanoscale porosity. Temperature dependent resistivity and magnetotransport measurements were conducted both on as-grown and porous samples (23 and 70 nm). The longitudinal resistivity of the porous samples became more metallic, indicating the increased surface area resulted in transport that was more surfacelike. Weak antilocalization was present in all samples, and remarkably the phase coherence length doubled in the porous samples. This increase is likely due to the large Fermi velocity of the Dirac surface states. Our results show that the introduction of nanoporosity does not destroy the topological surface states but rather enhances them, making these nanostructured materials promising for low energy electronics, spintronics and thermoelectrics.

AB - The surface area of Bi2Te3 thin films was increased by introducing nanoscale porosity. Temperature dependent resistivity and magnetotransport measurements were conducted both on as-grown and porous samples (23 and 70 nm). The longitudinal resistivity of the porous samples became more metallic, indicating the increased surface area resulted in transport that was more surfacelike. Weak antilocalization was present in all samples, and remarkably the phase coherence length doubled in the porous samples. This increase is likely due to the large Fermi velocity of the Dirac surface states. Our results show that the introduction of nanoporosity does not destroy the topological surface states but rather enhances them, making these nanostructured materials promising for low energy electronics, spintronics and thermoelectrics.

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Increased phase coherence length in a porous topological insulator

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ARC Centre of Excellence in Future Low-energy Electronics Technologies

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