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arXiv · 1409.5095

Aharonov-Bohm Oscillations in a Quasi-Ballistic 3D Topological Insulator Nanowire

S. Cho·B. Dellabetta·R. D. Zhong·J. Schneeloch·T. S. Liu·G. Gu·Matthew J. Gilbert·Nadya Mason
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Abstract

In three-dimensional topological insulators (3D TI) nanowires, transport occurs via gapless surface states where the spin is fixed perpendicular to the momentum[1-6]. Carriers encircling the surface thus acquire a \pi Berry phase, which is predicted to open up a gap in the lowest-energy 1D surface subband. Inserting a magnetic flux ({\Phi}) of h/2e through the nanowire should cancel the Berry phase and restore the gapless 1D mode[7-8]. However, this signature has been missing in transport experiments reported to date[9-11]. Here, we report measurements of mechanically-exfoliated 3D TI nanowires which exhibit Aharonov-Bohm oscillations consistent with topological surface transport. The use of low-doped, quasi-ballistic devices allows us to observe a minimum conductance at {\Phi} = 0 and a maximum conductance reaching e^2/h at {\Phi} = h/2e near the lowest subband (i.e. the Dirac point), as well as the carrier density dependence of the transport.

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S. Cho, B. Dellabetta, R. D. Zhong, J. Schneeloch, T. S. Liu, G. Gu, Matthew J. Gilbert, Nadya Mason. 2014-09-17. Aharonov-Bohm Oscillations in a Quasi-Ballistic 3D Topological Insulator Nanowire. https://doi.org/10.1038/ncomms8634

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