  In the framework of mean field approach, we study topological Mott transition
in a two band model of spinless fermions on a square lattice at half filling.
We consider the combined effect of the on-site Coulomb repulsion and the
spin-orbit Rashba coupling. The ground state phase diagram is calculated as a
function of the strength of the spin-orbit Rashba coupling and the Coulomb
repulsion. The spin-orbit Rashba coupling leads to a distinct phase of matter,
the topological semimetal. We study a new type of phase transition between the
non-topological insulator and topological semimetal states. Topological phase
state is characterized by the zero energy Majorana states, which there are in
defined region of the wave vectors and are localized at the boundaries of the
sample. The region of existence of the zero energy Majorana states tends to
zero at the point of the Mott phase transition. The zero energy Majorana states
are dispersionless (they can be considered as flat bands), the Chern number and
Hall conductance are equal to zero (note in two dimensional model
