Quantized Hall Effect and Shubnikov-de Haas Oscillations in Highly Doped Bi2Se3: Evidence for Layered Transport of Bulk Carriers

Bi₂Se₃ is an important semiconductor thermoelectric material and a prototype topological insulator. Here we report observation of Shubnikov-de Hass oscillations accompanied by quantized Hall resistances (R_xy) in highly doped n-type Bi₂Se₃ with bulk carrier concentrations of few 10¹⁹cm^-3. Measurements under tilted magnetic fields show that the magnetotransport is 2D-like, where only the c-axis component of the magnetic field controls the Landau level formation. The quantized step size in 1/R_xy is found to scale with the sample thickness, and average ∼e²/h per quintuple layer. We show that the observed magnetotransport features do not come from the sample surface, but arise from the bulk of the sample acting as many parallel 2D electron systems to give a multilayered quantum Hall effect. In addition to revealing a new electronic property of Bi₂Se₃, our finding also has important implications for electronic transport studies of topological insulator materials.