Yi M, Wang Meng, Kemper A F, Mo S-K, Hussain Z, Bourret-Courchesne E, Lanzara A, Hashimoto M, Lu D H, Shen Z-X, Birgeneau R J
Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
Computational Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Phys Rev Lett. 2015 Dec 18;115(25):256403. doi: 10.1103/PhysRevLett.115.256403. Epub 2015 Dec 15.
We present a systematic angle-resolved photoemission spectroscopy study of the substitution dependence of the electronic structure of Rb_{0.8}Fe_{2}(Se_{1-z}S_{z}){2} (z=0, 0.5, 1), where superconductivity is continuously suppressed into a metallic phase. Going from the nonsuperconducting Rb{0.8}Fe_{2}S_{2} to superconducting Rb_{0.8}Fe_{2}Se_{2}, we observe little change of the Fermi surface topology, but a reduction of the overall bandwidth by a factor of 2. Hence, for these heavily electron-doped iron chalcogenides, we have identified electron correlation as explicitly manifested in the quasiparticle bandwidth to be the important tuning parameter for superconductivity, and that moderate correlation is essential to achieving high T_{C}.
我们展示了一项关于Rb₀.₈Fe₂(Se₁₋zSz)₂（z = 0、0.5、1）电子结构的替代依赖性的系统角分辨光电子能谱研究，其中超导性被连续抑制到金属相。从非超导的Rb₀.₈Fe₂S₂到超导的Rb₀.₈Fe₂Se₂，我们观察到费米面拓扑结构几乎没有变化，但总带宽减小了2倍。因此，对于这些重电子掺杂的铁硫族化合物，我们确定在准粒子带宽中明确表现出的电子关联是超导性的重要调节参数，并且适度的关联对于实现高Tc至关重要。
