Electronic band structure in graphene: non-tight-binding vs. tight-binding bands

E. Kogan, V. U. Nazarov, V. M. Silkin

Published 2016-10-12Version 1

In our previous paper (Phys. Rev. B {\bf 89}, 165430 (2014)) we have found that in graphene the two lowest lying at the $\Gamma$-point unoccupied bands (one of them of a $\sigma$-like type and the other of a $\pi$-like one), are not of tight-binding model (TBM) type. In the present work we suggest a minimalistic model for these two bands. This description among other things predicts the symmetry of the bands. To compare these bands with the TBM ones we also present the symmetry analysis of the TBM bands, largely expanded with respect to our previous publications.