The transport length ltr and the mean free path le are experimentally determined for bulk and surface states in a Bi2Se3 nanoribbon by quantum transport and transconductance measurements. We show that the anisotropic scattering of spin-helical Dirac fermions results in a strong enhancement of ltr, which confirms theoretical predictions \cite{Culcer2010}. Despite strong disorder (le≈30~nm), our result further points to the long-range nature of the scattering potential, giving a large ratio ltr/le≈8 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.
@article{arxiv.1512.04439,
title = {Enhanced transport length of spin-helical Dirac fermions in disordered 3D topological insulators},
author = {J. Dufouleur and L. Veyrat and B. Dassonneville and C. Nowka and S. Hampel and P. Leksin and B. Eichler and O. G. Schmidt and B. Büchner and R. Giraud},
journal= {arXiv preprint arXiv:1512.04439},
year = {2024}
}