Unconventional integer quantum Hall effect in graphene

Phys Rev Lett. 2005 Sep 30;95(14):146801. doi: 10.1103/PhysRevLett.95.146801. Epub 2005 Sep 28.


Monolayer graphite films, or graphene, have quasiparticle excitations that can be described by (2+1)-dimensional Dirac theory. We demonstrate that this produces an unconventional form of the quantized Hall conductivity sigma(xy) = -(2e2/h)(2n+1) with n = 0, 1, ..., which notably distinguishes graphene from other materials where the integer quantum Hall effect was observed. This unconventional quantization is caused by the quantum anomaly of the n=0 Landau level and was discovered in recent experiments on ultrathin graphite films.