Abstract
We report on low-temperature transport and electronic band structure of p-type Sb2Te3 nanowires, grown by chemical vapor deposition. Magnetoresistance measurements unravel quantum interference phenomena, which depend on the cross-sectional dimensions of the nanowires. The observation of periodic Aharonov-Bohm-type oscillations is attributed to transport in topologically protected surface states in the Sb2Te3 nanowires. The study of universal conductance fluctuations demonstrates coherent transport along the Aharonov-Bohm paths encircling the rectangular cross-section of the nanowires. We use nanoscale angle-resolved photoemission spectroscopy on single nanowires (nano-ARPES) to provide direct experimental evidence on the nontrivial topological character of those surface states. The compiled study of the bandstructure and the magnetotransport response unambiguosly points out the presence of topologically protected surface states in the nanowires and their substantial contribution to the quantum transport effects, as well as the hole doping and Fermi velocity among other key issues. The results are consistent with the theoretical description of quantum transport in intrinsically doped quasi-one-dimensional topological insulator nanowires.
Highlights
To the opening of an energy-gap at the lowest subband of the surface state energy spectrum
The observation of AB-like oscillations is by itself no proof for transport in the topological surface states, since they have been observed for semiconducting nanowires with a surface accumulation layer due to band bending[17]
It is reported that the Φ0 periodicity occurs in quasi-one-dimensional Sb2Te3 nanowires grown by chemical vapor deposition
Summary
The observation of periodic Aharonov-Bohm-type oscillations is attributed to transport in topologically protected surface states in the Sb2Te3 nanowires. The compiled study of the bandstructure and the magnetotransport response unambiguosly points out the presence of topologically protected surface states in the nanowires and their substantial contribution to the quantum transport effects, as well as the hole doping and Fermi velocity among other key issues. The combined study of magnetotransport experiments, together with nano-ARPES, indicates that the observed AB-type oscillations in the presence of a parallel magentic field (B ) arise due to the presence of topologically protected two-dimensional surface channels and their contribution to the quantum transport effects in the Sb2Te3 TI nanowires. The further extracted coherence length and temperature dependence of the UCF pattern provides information on the average limit of the coherent-transport within the wire and its quasi-one-dimensional character along the wire axis
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