Noncentrosymmetric two-dimensional Weyl semimetals in porous Si/Ge structures.

In this work we predict a family of noncentrosymmetric two-dimensional (2D) Weyl semimetals (WSMs) composed by porous Ge and SiGe structures. These systems are energetically stable graphenylene-like structures with a buckling, spontaneously breaking the inversion symmetry. The nontrivial topological phase for these 2D systems occurs just below the Fermi level, resulting in nonvanishing Berry curvature around the Weyl nodes.