State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People's Republic of China.
Phys Rev Lett. 2010 Sep 10;105(11):117002. doi: 10.1103/PhysRevLett.105.117002. Epub 2010 Sep 8.
The electronic structure of NaFeAs is studied with angle-resolved photoemission spectroscopy on high quality single crystals. Large portions of the band structure start to shift around the structural transition temperature and smoothly evolve as the temperature lowers through the spin density wave transition. Moreover, band folding due to magnetic order emerges slightly above the structural transition. Our observation provides direct evidence that the structural and magnetic transitions share the same origin and could both be driven by the electronic structure reconstruction in Fe-based superconductors instead of Fermi surface nesting. We did not observe any sign of a gap in the superconducting state, which is likely related to weakened superconductivity in the presence of the spin density wave.
采用角分辨光电子能谱对高质量的单晶 NaFeAs 进行了电子结构研究。在结构相变温度附近，大部分能带结构开始移动，并在自旋密度波相变温度降低时平滑演变。此外，由于磁场有序，能带折叠在结构相变之上略微出现。我们的观察提供了直接证据，表明结构和磁转变具有相同的起源，并且都可以由 Fe 基超导体中的电子结构重构而不是费米面嵌套驱动。我们在超导状态下没有观察到任何能隙的迹象，这可能与自旋密度波存在时超导性减弱有关。
