Using the numerical unrestricted Hartree-Fock approach, we study the ground state of a two-orbital model describing newly discovered FeAs-based superconductors. We observe the competition of a （0, π） mode spin-dens...Using the numerical unrestricted Hartree-Fock approach, we study the ground state of a two-orbital model describing newly discovered FeAs-based superconductors. We observe the competition of a （0, π） mode spin-density wave and the superconductivity as the doping concentration changes. side where the magnetism and superconductivity coexist. The orbital even, and coexisting sxy ＋dx^2-y^2 wave （even parity）. There might be a small region in the electron-doping superconducting pairing is found to be spin singlet,展开更多
By comparing the data of lattice parameters of more than 50 new FeAs-based high temperature superconductors in two syetems, the effect of bondlength on superconducting transition temperature (T C ) was found that, for...By comparing the data of lattice parameters of more than 50 new FeAs-based high temperature superconductors in two syetems, the effect of bondlength on superconducting transition temperature (T C ) was found that, for both FeAs superconductor systems with similar ionic radii of cation A, the bond length L As-A between Arsenic atom and its nearest neighbor cation at the A site is in an inverse proportion to T C , i.e. the larger the bond length L As-A , the lower the T C . In addition, we also found a noticeable effect of ionic radius on T C , in which deviation from the tendency line of bond length vs. T C decreases with the increasing ionic radius. Both bond length-T C and ionic radii-T C relations indicate that the interaction of cation A and As ion have significant effect on superconductivity. The analysis on the electronic structure indicates that there exists the proximity of the secondary-outer p-orbit of the cation A and the 4s orbit of the As ion, both in energy space and in real space. Some high frequency individual vibrating modes would be established through exchange coupling on their inner orbits. It is worth of mention that the superconducting condensation is influenced by the interaction between the cation A and the As atoms.展开更多
基金Project supported by the Earmarked Grant for Research from the Research Grants Council of HKSAR,China (Grant Nos CUHK402205 and HKU3/05C)
文摘Using the numerical unrestricted Hartree-Fock approach, we study the ground state of a two-orbital model describing newly discovered FeAs-based superconductors. We observe the competition of a （0, π） mode spin-density wave and the superconductivity as the doping concentration changes. side where the magnetism and superconductivity coexist. The orbital even, and coexisting sxy ＋dx^2-y^2 wave （even parity）. There might be a small region in the electron-doping superconducting pairing is found to be spin singlet,
基金Supported by the National Science Foundation of USA (Grant No.DMR-0821284)the National Natural Science Foundation of China (Grant No. 50372005)the Natural Science Foundation of Beijing (Grant No.1072007)
文摘By comparing the data of lattice parameters of more than 50 new FeAs-based high temperature superconductors in two syetems, the effect of bondlength on superconducting transition temperature (T C ) was found that, for both FeAs superconductor systems with similar ionic radii of cation A, the bond length L As-A between Arsenic atom and its nearest neighbor cation at the A site is in an inverse proportion to T C , i.e. the larger the bond length L As-A , the lower the T C . In addition, we also found a noticeable effect of ionic radius on T C , in which deviation from the tendency line of bond length vs. T C decreases with the increasing ionic radius. Both bond length-T C and ionic radii-T C relations indicate that the interaction of cation A and As ion have significant effect on superconductivity. The analysis on the electronic structure indicates that there exists the proximity of the secondary-outer p-orbit of the cation A and the 4s orbit of the As ion, both in energy space and in real space. Some high frequency individual vibrating modes would be established through exchange coupling on their inner orbits. It is worth of mention that the superconducting condensation is influenced by the interaction between the cation A and the As atoms.
