Superconductivity and topologically nontrivial states in noncentrosymmetric XVSe2 (X = Pb, Sn): a first-principles study

Noncentrosymmetric superconductors are strong candidates for exploring intrinsic topological superconductivity. Here, we predict two new noncentrosymmetric superconductors SnVSe2 and PbVSe2 by a systematic first-principles study. These two compounds show good thermal and dynamic stabilities. Moreover, the band topology of both compounds is predicted to be nontrivial via Z(2) calculation and slab models. We also investigate the electron-phonon interactions in SnVSe2 and PbVSe2, indicating the T-c of SnVSe2 and PbVSe2 without external pressure are predicted to be similar to 1.18 K and similar to 0.22 K, respectively. Furthermore, the results on pressure engineering in PbVSe2 imply that the T-c of PbVSe2 can be tuned to 2.39 K for enhanced contributions from Pb layers under pressure up to 6.4 GPa. This work may provide new platforms for probing spin-triplet paring and may help with designing and developing new metal-intercalated transition metal dichalcogenides.

Automated summary

In this study, two new noncentrosymmetric superconductors SnVSe2 and PbVSe2 were predicted via systematic first-principles study, showing good thermal and dynamic stabilities and nontrivial band topology. The investigation also revealed the electron-phonon interactions in SnVSe2 and PbVSe2, as well as the possibility of tuning the T-c of PbVSe2 through pressure engineering. This work may provide new insights into spin-triplet pairing and aid in the development of new metal-intercalated transition metal dichalcogenides.