Thickness-dependent electrical transport in weak topological insulator Bi1Se1

Weak topological insulators are elusive topological materials that were subjected to relatively few experimental studies in the past owing to the lack of stable systems. Here, a detailed investigation of the low-temperature electrical transport on Bi 1 Se 1 thin films, a weak topological insulator, over a wide range of thicknesses has been carried out. Robust signatures of weak anti-localization were observed from the electrical transport measurements where the magnetic field is applied perpendicular and parallel to the sample plane. The low-field data are analyzed using the Hikami–Larkin–Nagaoka equation. By combining the transport parameters ( α, L ϕ) extracted from both perpendicular and parallel field measurements, our results indicate that apart from three-dimensional bulk states, 2D surface states are also present in our system and their origin could be linked to the weak topological nature of Bi 1 Se 1.