LnPd₂Sn (Ln=Sc, Y, Lu) class of Heusler alloys for topological superconductivity

Based on the first-principles electronic structure calculations and the symmetry analysis, we predict that the topological superconductivity may occur on the surface of the LnPd$_{2}$Sn (Ln=Sc, Y, Lu) class of Heusler alloys. The calculated electronic band structure and topological invariant demonstrate that the LnPd$_{2}$Sn family is topologically nontrivial. The further slab calculations show that the nontrivial topological surface states of LnPd$_{2}$Sn exist within the bulk band gap and meanwhile they cross the Fermi level. Considering that the LnPd$_{2}$Sn class of compounds were all found experimentally to be superconducting at low temperature, the surface topological superconductivity is likely to be generated via the proximity effect. Thus the LnPd$_{2}$Sn class of compounds shall be a promising platform for exploring novel topological superconductivity and handling Majorana zero modes.