  We theoretically study a tunneling effect in a two-dimensional Dirac
semimetal with two Dirac points protected by non-symmorphic symmetries. The
tunnel barrier can be arranged by a magnetic exchange potential which opens a
gap at the Dirac points which can be induced by a magnetic proximity effect of
a ferromagnetic insulator. We found that the tunnel decay length increases with
a decrease in the strength of the spin-orbit coupling, and moreover the
dependence is attributed to the correlation of sublattice and spin degree of
freedoms which lead to symmetry-protected Dirac points. The tunnel probability
is quite different in two Dirac points, and thus the tunnel effect can be
applied to the highly-selective valley filter.

Mesoscale and Nanoscale Physics