Spin-orbit torque in a thin film of the topological insulator Bi2Se3: Crossover from the ballistic to diffusive regimeY. J. Ren, W. Y. Deng, H. Geng, R. Shen, L. B. Shao, L. Sheng and D. Y. XingEPL, 120 5 (2017) 57004DOI: https://doi.org/10.1209/0295-5075/120/57004