摘要 :
High-resolution angle-resolved photoemission measurements have been carried out on the (Sr,K)Fe_2As_2 superconductor (T_c=21 K). Three holelike Fermi-surface sheets are resolved around the Γ point. One electronlike Fermi surface ...
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High-resolution angle-resolved photoemission measurements have been carried out on the (Sr,K)Fe_2As_2 superconductor (T_c=21 K). Three holelike Fermi-surface sheets are resolved around the Γ point. One electronlike Fermi surface and strong Fermi spots are observed near the M(π,π) point which are different from a round electron pocket expected from band calculations. This discrepancy and the observed band renormalization ask for further theoretical effort in understanding the electronic structure of the Fe-based compounds.
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摘要 :
We use powder neutron diffraction to study the spin and lattice structures of polycrystalline samples of nonsuperconducting PrFeAsO and superconducting PrFeAsO_(0.85)F_(0.15) and PrFeAsO_(0.85).We find that PrFeAsO exhibits abrupt...
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We use powder neutron diffraction to study the spin and lattice structures of polycrystalline samples of nonsuperconducting PrFeAsO and superconducting PrFeAsO_(0.85)F_(0.15) and PrFeAsO_(0.85).We find that PrFeAsO exhibits abrupt structural phase transitions at 153 K followed by static long-range antiferromagnetic order at 127 K. Both the structural distortion and magnetic order are similar to other rare-earth oxypnictides. Electron doping the system with either fluorine or oxygen deficiency suppresses the structural distortion and static long-range antiferromagnetic order, therefore placing these materials into the same class of FeAs-based superconductors.
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