Study Of Superconductivity Of Two-dimensional Transition Metal Compounds Intercalated With Alkali Metals Based On First Principles

Superconducting materials have attracted a lot of attention because of their characteristics such as zero resistance effect and Meiners effect under specific conditions.Among them,two-dimensional superconducting materials usually exhibit excellent superconductivity and have become one of the hot spots in the field of superconducting materials research.The intercalation technique can effectively modulate the superconductivity of two-dimensional materials,providing a direction for the study of two-dimensional superconductivity.This work investigates the superconductivity of alkali metal intercalated bilayer transition metal compounds 1TPtTe2 and Mo2C and their superconducting microscopic mechanisms using firstprinciples calculations,providing a good platform for future studies of physical properties related to two-dimensional superconductivity and further promoting the research development of two-dimensional superconductors.Conclusions of the research work in this paper:1.The alkali metal atoms intercalated bilayer 1T-PtTe2 formed a stable structure with stoichiometric ratio MPt2Te4(M=Li/Na/K/Rb/C s).In the MPt2Te4 system,RbPt2Te4 structure is the one with the highest superconducting transition temperature of 11.5 K.The enhanced electroacoustic coupling of the electrons in the p-orbital of the Te atom and the d-orbital of the Pt atom with the phonon vibrations of the Te,Rb,and Pt atoms enhances the superconductivity of the RbPt2Te4.Spin-orbit coupling inhibits the superconductivity of the RbPt2Te4 structure,leading to a decrease in its superconductivity.structure.In addition,the alkali metal Li/Na/K/Rb/Cs atomic intercalation bilayer 1T-PtTe2 has superconducting transition temperatures of 4 K,4 K,11 K,11.5 K,and 7 K,respectively,and they are all higher(without considering the spin-orbit coupling effect)than those of the bilayer 1T-PtTe2 structure(1.1 K).2.The alkali metal Li atoms intercalated with bilayered Mo2C formed three stable structures of Taa-Li(Mo2C)2,Tm-Li(Mo2C)2 and Tab-Li(Mo2C)2 with the stoichiometry of Li(Mo2C)2.The superconductivity of the Li(Mo2C)2 system is enhanced by the electroacoustic coupling of the electrons in the d orbitals of the Mo atom with the enhanced in-plane and out-of-plane phonon vibrations of the Mo atom.Taa-Li(Mo2C)2,Tm-Li(Mo2C)2,and Tab-Li(Mo2C)2 have superconducting transition temperatures of 11.3 K,10.4 K,and 9.2 K,respectively.In addition,bilayer Mo2C is a non-superconductor.