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arXiv · 1512.04439

Enhanced transport length of spin-helical Dirac fermions in disordered 3D topological insulators

J. Dufouleur·L. Veyrat·B. Dassonneville·C. Nowka·S. Hampel·P. Leksin·B. Eichler·O. G. Schmidt·B. Büchner·R. Giraud
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Abstract

The transport length $l_\textrm{tr}$ and the mean free path $l_\textrm{e}$ are experimentally determined for bulk and surface states in a Bi$_2$Se$_3$ nanoribbon by quantum transport and transconductance measurements. We show that the anisotropic scattering of spin-helical Dirac fermions results in a strong enhancement of $l_\textrm{tr}$, which confirms theoretical predictions \cite{Culcer2010}. Despite strong disorder ($l_\textrm{e}\approx30$~nm), our result further points to the long-range nature of the scattering potential, giving a large ratio $l_\textrm{tr}/l_\textrm{e}\approx8$ that is likely limited by a finite bulk/surface coupling. This suggests that the spin-flip length could reach the micron size in disordered 3D topological insulator nanostructures with a reduced bulk doping, even if due to charge compensation.

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J. Dufouleur, L. Veyrat, B. Dassonneville, C. Nowka, S. Hampel, P. Leksin, B. Eichler, O. G. Schmidt, B. Büchner, R. Giraud. 2015-12-14. Enhanced transport length of spin-helical Dirac fermions in disordered 3D topological insulators. https://doi.org/10.1021/acs.nanolett.6b02060

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