Magneto-optics of massive Dirac fermions in bulk Bi2Se3

TL;DR

This paper investigates the magneto-optical properties of bulk Bi2Se3, showing it can be modeled as massive Dirac fermions with a unique spin splitting property, distinguishing it from quantum electrodynamics predictions.

Contribution

It demonstrates that bulk Bi2Se3's electronic states are well described by a simple Dirac Hamiltonian with a distinctive spin splitting relation, advancing understanding of topological insulator physics.

Findings

Spin splitting equals twice the cyclotron energy (Es=2Ec).

The Dirac model accurately describes bulk Bi2Se3's electronic states.

Distinctive spin splitting differentiates it from quantum electrodynamics.

Abstract

We report on magneto-optical studies of Bi2Se3, a representative member of the 3D topological insulator family. Its electronic states in bulk are shown to be well described by a simple Dirac-type Hamiltonian for massive particles with only two parameters: the fundamental bandgap and the band velocity. In a magnetic field, this model implies a unique property - spin splitting equal to twice the cyclotron energy: Es = 2Ec. This explains the extensive magneto-transport studies concluding a fortuitous degeneracy of the spin and orbital split Landau levels in this material. The Es = 2Ec match differentiates the massive Dirac electrons in bulk Bi2Se3 from those in quantum electrodynamics, for which Es = Ec always holds.