Weyl fermion on reconstructed surface of Bi/Si(110) with non-symmorphic lattice symmetry

In two-dimensional crystals, the non-symmorphic lattice symmetry together with time reversal symmetry can stabilize Weyl fermionic states. With 4n+2 electron filling, the states can be tuned to locate near the charge neutral point. Here, using first-principles calculations, we propose a stable Bi adatom induced superstructure on Si(110) surface, characterized by wallpaper symmetry group pg, as a candidate system for the realization of Weyl fermion states with 4n+2 electron filling. Out of various adsorption geometries, the ground structure bears single glide line parallel to [1-10] direction, results in a two-fold degenerate Bloch bands along glide lines. We will also discuss a way of controlling band dispersions where the Weyl fermion reside near the fermi level.