Higher-order topological and nodal superconducting transition-metal sulfides <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>M</mml:mi><mml:mi mathvariant="normal">S</mml:mi></mml:mrow><mml:mo> </mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mi>M</mml:mi><mml:mo>=</mml:mo><mml:mi>Nb</mml:mi><mml:mo> </mml:mo><mml:mtext>and</mml:mtext><mml:mo> </mml:mo><mml:mi>Ta</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math>
Yipeng An, Juncai Chen, Yong Yan, Jinfeng Wang, Yinong Zhou, Zhengxuan Wang, Chunlan Ma, Tianxing Wang, Ruqian Wu, Wu‐Ming Liu
Abstract
Intrinsic topological superconducting materials are exotic and vital to develop the next-generation topological superconducting devices, topological quantum calculations, and quantum information technologies. Here, we predict the topological and nodal superconductivity of NiAs-type $M\mathrm{S}$ $(M=\mathrm{Nb}\text{and}\mathrm{Ta})$ transition-metal sulfides. We reveal their higher-order topology nature with an index of ${Z}_{4}=2$. These materials have a higher ${T}_{\mathrm{c}}$ than the Nb or Ta metal superconductors due to their flat band and strong electron-phonon coupling nature. Electron doping and lighter isotopes can effectively enhance the ${T}_{\mathrm{c}}$. Our findings show that the $M\mathrm{S}$ $(M=\mathrm{Nb}\text{and}\mathrm{Ta})$ systems can be platforms to study exotic physics in the higher-order topological superconductors, and provide a theoretical support to utilize them as the topological superconducting devices in the field of advanced topological quantum calculations and information technologies.