Abstract
In a magnetic field, bilayer graphene supports an octet of zero-energy Landau levels with an extra twofold degeneracy in Landau orbitals and 1. It is shown that this orbital degeneracy is lifted due to Coulombic quantum fluctuations of the valence band (the Dirac sea); this is a quantum effect analogous to the Lamb shift in the hydrogen atom. A detailed study is made of how these zero-energy levels evolve, with filling, into a variety of pseudo-zero-mode Landau levels in the presence of possible spin and valley breaking and Coulomb interactions, and a comparison is made with experimental results.
- Received 9 April 2012
DOI:https://doi.org/10.1103/PhysRevB.86.045431
©2012 American Physical Society