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

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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 languageEnglish
Article number064202
Number of pages6
JournalPhysical Review Materials
Issue number6
Publication statusPublished - 15 Jun 2023

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