We report comprehensive angle-resolved photoemission investigations on the electronic structures and nematicity of the parent compounds of the iron-based superconductors including CeFeAsO, BaFe2As2, NaFeAs, FeSe and u...We report comprehensive angle-resolved photoemission investigations on the electronic structures and nematicity of the parent compounds of the iron-based superconductors including CeFeAsO, BaFe2As2, NaFeAs, FeSe and undoped FeSe/SrTiO3 films with 1, 2 and 20 layers. While the electronic structure near tile Brillouin zone center F varies dramatically among different materials, the electronic structure near the Brillouin zone corners （M points）, as well as their temperature dependence, are rather similar. The electronic structure near the zone corners is dominated by the electronic nematicity that gives rise to a band splitting of the dxz and dyz bands below the nematie transition temperature. A clear relation is observed between the band splitting magnitude arid the onset temperature of nematicity. Our results may shed light on the origin of nematicity, its effect on the electronic structures, and its relation with superconductivity in the iron-based superconductors.展开更多
SrTiO3 nanorods were synthesized in cetanyl trimethyl ammonium bromide(CTAB)reverse microemulsion containing CTAB,n-hexanol,n-octane and water with Ba(OH)2 as reactants.The effects of different conditions such as ω0 ...SrTiO3 nanorods were synthesized in cetanyl trimethyl ammonium bromide(CTAB)reverse microemulsion containing CTAB,n-hexanol,n-octane and water with Ba(OH)2 as reactants.The effects of different conditions such as ω0 [ω0=n /nCTAB],aging time and the concentration of reactants on the formation of the nanorods were studied.Transmission electron microscope(TEM),electron diffraction(ED)and X-ray diffraction(XRD)were used to characterize the morphology and the structure of the synthesized nanorods.The results show that SrTiO3 nanorods with a length of 260～2 000 nm and a diameter of 50～100 nm belonging to single crystal are single cubic system.The molar ratio of Sr to Ti of products is 1.0 as determinded by ICP.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11190022,11334010 and 11534007the National Basic Research Program of China under Grant No 2015CB921000the Strategic Priority Research Program(B)of Chinese Academy of Sciences under Grant No XDB07020300
文摘We report comprehensive angle-resolved photoemission investigations on the electronic structures and nematicity of the parent compounds of the iron-based superconductors including CeFeAsO, BaFe2As2, NaFeAs, FeSe and undoped FeSe/SrTiO3 films with 1, 2 and 20 layers. While the electronic structure near tile Brillouin zone center F varies dramatically among different materials, the electronic structure near the Brillouin zone corners （M points）, as well as their temperature dependence, are rather similar. The electronic structure near the zone corners is dominated by the electronic nematicity that gives rise to a band splitting of the dxz and dyz bands below the nematie transition temperature. A clear relation is observed between the band splitting magnitude arid the onset temperature of nematicity. Our results may shed light on the origin of nematicity, its effect on the electronic structures, and its relation with superconductivity in the iron-based superconductors.
文摘SrTiO3 nanorods were synthesized in cetanyl trimethyl ammonium bromide(CTAB)reverse microemulsion containing CTAB,n-hexanol,n-octane and water with Ba(OH)2 as reactants.The effects of different conditions such as ω0 [ω0=n /nCTAB],aging time and the concentration of reactants on the formation of the nanorods were studied.Transmission electron microscope(TEM),electron diffraction(ED)and X-ray diffraction(XRD)were used to characterize the morphology and the structure of the synthesized nanorods.The results show that SrTiO3 nanorods with a length of 260～2 000 nm and a diameter of 50～100 nm belonging to single crystal are single cubic system.The molar ratio of Sr to Ti of products is 1.0 as determinded by ICP.
