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.
@article{arxiv.1504.02791,
title = {Magneto-optics of massive Dirac fermions in bulk Bi2Se3},
author = {M. Orlita and B. A. Piot and G. Martinez and N. K. Sampath Kumar and C. Faugeras and M. Potemski and C. Michel and E. M. Hankiewicz and T. Brauner and Č. Drašar and S. Schreyeck and S. Grauer and K. Brunner and C. Gould and C. Brüne and L. W. Molenkamp},
journal= {arXiv preprint arXiv:1504.02791},
year = {2015}
}
Comments
5 pages, 3 figures and Supplementary materials, to be published in Physical Review Letters