Far infrared cyclotron resonance and Faraday effect in Bi2Se3

TL;DR

This study investigates the far infrared optical properties of Bi2Se3, a topological insulator, revealing bulk carrier dominance, electron-like carriers, and specific cyclotron mass and electron concentration measurements.

Contribution

It provides the first detailed analysis of Faraday rotation and transmission in Bi2Se3 using a magneto-plasma model, highlighting bulk carrier properties.

Findings

Bulk carriers dominate the optical response.

Bulk carriers are electrons, confirmed by Faraday angle sign.

Measured cyclotron mass is 0.16 m_e with low electron concentration.

Abstract

The complex Faraday angle and transmission for the topological insulator Bi2Se3 were measured in the far infrared in magnetic fields up to 8 T and analyzed in terms of a simple Drude-Lorentz magneto-plasma dielectric model. Bulk carriers dominate the optical response. The bulk carriers are electrons as we determined from the sign of the Faraday angle. We obtain the bulk band edge cyclotron mass m_cb = 0.16 +- 0.01 m_e and free electron concentration in the 10^17 range. Electron-phonon interaction effects were found to be weak.