Richard P, Sato T, Nakayama K, Souma S, Takahashi T, Xu Y-M, Chen G F, Luo J L, Wang N L, Ding H
WPI Research Center, Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Phys Rev Lett. 2009 Jan 30;102(4):047003. doi: 10.1103/PhysRevLett.102.047003. Epub 2009 Jan 27.
We have performed an angle-resolved photoemission spectroscopy study of the new superconductor Ba0.6K0.4Fe2As2 in the low energy range. We report the observation of an anomaly around 25 meV in the dispersion of superconducting Ba0.6K0.4Fe2As2 samples that nearly vanishes above T_{c}. The energy scale of the related mode (13+/-2 meV) and its strong dependence on orbital and temperature indicates that it is unlikely related to phonons. Moreover, the momentum locations of the kink can be connected by the antiferromagnetic wave vector. Our results point towards an unconventional electronic origin of the mode and the superconducting pairing in the Fe-based superconductors, and strongly support the antiphase s-wave pairing symmetry.
我们对新型超导体Ba0.6K0.4Fe2As2在低能范围内进行了角分辨光电子能谱研究。我们报告了在超导Ba0.6K0.4Fe2As2样品的色散中观测到约25毫电子伏特处的一个异常，该异常在高于Tc时几乎消失。相关模式的能量尺度（13±2毫电子伏特）及其对轨道和温度的强烈依赖性表明它不太可能与声子有关。此外，扭折的动量位置可以由反铁磁波矢连接起来。我们的结果指向该模式和铁基超导体中超导配对的非常规电子起源，并有力地支持反相位s波配对对称性。
