In the physics of two-dimensional materials, notion semi-Dirac dispersion denotes electronic dispersion which is Dirac-like along one direction in the reciprocal space, and quadratic along the orthogonal direction. In our earlier publication (Damljanović and Gajić in J Phys Condens Matter 29:185503, 2017) we have shown that certain layer groups are particularly suitable for hosting semi-Dirac dispersion in the vicinity of some points in the Brillouin zone (BZ). In the present paper we have considered tight-binding model up to seventh nearest neighbors, on a structure belonging to layer group Dg5. According to our theory, this group should host semi-Dirac dispersion at A and B points in the BZ. The structure has four atoms per primitive cell, and it is isostructural with sublattice occupied by phosphorus atoms in the layered material SnPSe3
Two-dimensional (2D) materials are materials that are periodic in two spatial directions but finite in the third, orthogonal direction. These materials gain particular attention after discovery of graphene, a one atom thick layer of carbon atoms arranged in a honeycomb lattice. In contrast to graphene, in which all atoms belong to a single plane, buckled silicene and germanene for example, occupy Wyckoff positions with unequal z-coordinates. Existence of massless electrons whose dynamics is described by Dirac (Weyl) equation is among notable properties of graphene and related, so called Dirac, materials.
