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

TL;DR

This study demonstrates layered bulk transport in highly-doped Bi2Se3 through quantized Hall effects and SdH oscillations, revealing its 2D-like multilayered electronic behavior which impacts topological insulator research.

Contribution

It provides evidence that bulk carriers in Bi2Se3 exhibit layered 2D transport, challenging the assumption that quantum Hall effects originate only from surface states.

Findings

Quantized Hall resistance observed in bulk Bi2Se3.

Magnetotransport is 2D-like under tilted magnetic fields.

Quantized step size scales with sample thickness, ~e2/h per quintuple layer.

Abstract

Bi2Se3 is an important semiconductor thermoelectric material and a prototype topological insulator. Here we report observation of Shubnikov-de Hass (SdH) oscillations accompanied by quantized Hall resistances (Rxy) in highly-doped n-type Bi2Se3 with bulk carrier concentrations of few 10^19 cm^-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/Rxy is found to scale with the sample thickness, and average ~e2/h per quintuple layer (QL). 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. Besides revealing a new electronic property of Bi2Se3, our finding also has important implications for electronic transport studies of topological insulator materials.