The First Principle Calculations Of Pt-based Superconducting Materials

The discovery of iron-based high-Tc superconductors has stimulated considerable interest in the condensed-matter physics society. Sharing similar layered lattice crystal structures, both iron-based materials which include iron-based layer (FeAs/FeSe/FeTe) and earlier copper oxide superconductors that exhibit long-range magnetic order in parent compounds and unconventional superconductivity (SC) upon doping. In these3d transition-metal-based materials, the electron correlation effect is considered to play an important role in the formation of the spin-density-wave (SDW).With superconducting materials study further, more and more different system of superconducting materials was found.In this article, mainly introduces the first principles of the density functional theory, and performs first principles calculation to depict several kinds of new synthetic materials which relationship between the magnetic and superconducting transition, and analyzes its electron and phonon spectrum, provide theoretical support for experiment. We found that the inserted layer of Cr-42622material containing magnetic elements, and spacing between two adjacent to iron-base layers compared to the other system of iron-based superconductor has more space distance, magnetic atoms doped and space span tensile electronic structure changes caused by iron base materials, and impact on the material physical properties. At the same time, the research of electron and phonon spectrum of APt3P shows the Fermi surfaces of the materials consist of multiple sheets. The spin orbit coupling effect played a very important role in LaPt3P,the SOC effect is negligible in BaPt3P、SrPt3P and CaPt3P,instead.In this, we predict the SrPt3P exist CDW instability, and the instability(the emergence of soften phonons) is absent in CaPt3P and can be quickly suppressed by the external pressure. Our results suggest SrPt3P as a rare example where superconductivity is enhanced by the CDW fluctuations. Finally, to study electronic and phonon properties of Pt/Pd-based materials of hexagonal grid structure. The valence band of these materials near the Fermi surface mainly comes from Pt-5d and Pd-4d orbitals, instead of the contribution of alkaline earth metal elements and As is relatively small near the Fermi surface, meanwhile they have quasi-two-dimensional hole-like the Fermi surface.