  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 effects of the on-site Coulomb repulsion and the
spin-orbit Rashba coupling. The spin-orbit Rashba coupling leads to a distinct
phase of matter, the topological semimetal. We are talking about a new type of
phase transition between the non-topological insulator state and topological
semimetal state. New 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 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).(note in two
dimensional model).
