The density of states of d -dimensional Dirac matter near the Dirac point scales as N ( ϵ ϵ ) ∝ ∝ | ϵ ϵ | d − − 1 where ϵ ϵ is the particle energy. The vanishing density of states for quasiparticles in Dirac matter mimics semimetal physics for physical dimension d > 1 . In the two-dimensional systems such as graphene and topological insulators, the density of states gives a V shape, compared with the constant value for massive particles with dispersion E = ℏ ℏ 2 k 2 / 2 m .