Angle resolved photoemission spectroscopy of Ba(Fe1-xCo x)2As2 (x = 0:06, 0.14, and 0.24) shows that the width of the Fe 3dyz/zx hole band depends on the doping level. In contrast, the Fe 3dx2-y2 and 3z2 - r2 bands are rigid and shifted by the Co doping. The Fe 3dyz/zx hole band is flattened at the optimal doping level x = 0:06, indicating that the band renormalization of the Fe 3dyz/zx band correlates with the enhancement of the superconducting transition temperature. The orbital-dependent and doping-dependent band renormalization indicates that the fluctuations responsible for the superconductivity is deeply related to the Fe 3d orbital degeneracy.
- Angle-resolved photoemission spectroscopy
- Band renormalization
- Fe-based superconductors
- Orbital degeneracy