Silicene and transition metal based materials: prediction of a two-dimensional piezomagnet

What is it about?

We use first-principles density functional theory based calculations to determine the stability and properties of silicene, a graphene-like structure made from silicon, and explore the possibilities of modifying its structure and properties through incorporation of transition metal ions (M: Ti, Nb, Ta, Cr, Mo and W) in its lattice, forming MSi2. While pure silicene is stable in a distorted honeycomb lattice structure obtained by opposite out-of-plane displacements of the two Si sub-lattices.

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Why is it important?

We show that silicene in its pure form exhibits a distortion of the honeycomb lattice, yet an interesting electronic structure with a linear dispersion similar to that of massless Dirac fermions in graphene, but with a smaller energy scale. Secondly, Ti and Ta silicenes exhibit planar honeycomb lattices supported by the triangular lattice of metal atoms. NbSi 2 with its highly asymmetric structure has the largest mechanical stiffness.