A family of robust Dirac cone materials: two-dimensional hexagonal M3X2 (M = Zn/Cd/Hg, X = Si/Ge)

The first-principles calculations shows that the 2D Dirac cone material M 3 X 2 (M = Zn/Cd/Hg, X = Si/Ge) with a highly fermi velocity and possess a robust Dirac cone even under biaxial strain or being sheared into one-dimensional zigzag nanoribbons.