Gregory W. Holloway, Daryoush Shiri, Chris M. Haapamaki, Kyle Willick, Grant Watson, Ray R. LaPierre, Jonathan Baugh
We study axial-field magnetoconductance in InAs core-shell nanowire field-effect transistors, finding oscillatory behaviour at low temperatures when the device is in accumulation mode. The primary oscillations have the periodicity of the flux quantum corresponding to an effective radius close to the InAs core radius. The magnetoconductance as a function of gate voltage matches well to theory based on coherent electronic states in a cylindrical shell near the surface, i.e. a two-dimensional electron gas. This implies an electronic phase coherence length >163 nm at a temperature of 3.8 K. It is remarkable that such coherent quantum effects can be observed in the diffusive transport regime, with a device length (1.2 \mu m) much greater than the elastic scattering length. These results suggest a high degree of crystalline order at the InAs-InAlAs interface, a key necessity for utilizing core-shell nanowires in coherent quantum device experiments.
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http://arxiv.org/abs/1305.5552
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