  We investigate the electronic properties of MXenes by three bands
tight-binding model of \d_{z^2} , \d_{xy} , and \d_{x^2-y^2} orbitals. The
three corresponding bands touch each other at high symmetry K point in the case
of absence of spin-orbit interaction. The proper parameters can be obtained by
Slater-Koster parameters related to chemical bonding, \pi, \sigma, and \delta
bonds. The model calculated for these band structures make an agreement with
the same trend as discussed in DFT calculation which the hopping parameters may
be identified roughly by fermi velocity. Furthermore, the triplet fermion
occurs around K point hosting by flat band, leading to super-Klein tunnelling
and anti-super-Klein tunnelling for gapped and gapless pseudospin-1 fermion,
respectively. These may apply for nanodevices operated by spin polarization
which is more stable than that of the conventional two-dimensional materials.
