Tunneling Conductance in a Two-dimensional Dirac Semimetal Protected by Non-symmorphic Symmetry

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.