Prediction of superconductivity in a series of tetragonal transition metal dichalcogenides.

Transition metal dichalcogenides (TMDCs) represent a well-known material family with diverse structural phases and rich electronic properties; they are thus an ideal platform for studying the emergence and exotic phenomenon of superconductivity (SC). Herein, we propose the existence of tetragonal TMDCs with a distorted Lieb ( d Lieb) lattice structure and the stabilized transition metal disulfides (MS2 ), including d Lieb-ZrS2 , d Lieb-NbS2 , d Lieb-MnS2 , d Lieb-FeS2 , d Lieb-ReS2 , and d Lieb-OsS2 . Except for semiconducting d Lieb-ZrS2 and magnetic d Lieb-MnS2 , the rest of metallic d Lieb-MS2 was found to exhibit intrinsic SC with the transition temperature ( T C ) ranging from ∼5.4 to ∼13.0 K. The T C of d Lieb-ReS2 and d Lieb-OsS2 exceeded 10 K and was higher than that of the intrinsic SC in the known metallic TMDCs, which is attributed to the significant phonon-softening enhanced electron-phonon coupling strength. Different from the Ising spin-orbit coupling (SOC) effect in existing non-centrosymmetric TMDCs, the non-magnetic d Lieb-MS2 monolayers exhibit the Dresselhaus SOC effect, which is featured by in-plane spin orientations and will give rise to the topological SC under proper conditions. In addition to enriching the structural phases of TMDCs, our work predicts a series of SC candidates with high intrinsic T C and topological non-triviality used for fault-tolerant quantum computation.