1206.4402 (S. T. Cui et al.)

Evolution of band structure from optimally doped to heavily overdoped
Co-substituted NaFeAs    [PDF]

S. T. Cui, S. Y. Zhu, A. F. Wang, S. Kong, S. L. Ju, X. G. Luo, X. H. Chen, G. B. Zhang, Z. Sun

Using angle-resolved photoemission spectroscopy, we studied the electronic structure of NaFe$_{1-x}$Co$_x$As from an optimally doped superconducting compound ($x=0.028$) to a heavily overdoped non-superconducting one ($x=0.109$). Similar to the case of "122" type iron pnictides, our data suggest that Co dopant in NaFe$_{1-x}$Co$_x$As supplies extra charge carriers and shifts the Fermi level accordingly. In the $x=0.109$ compound, the hole-like bands around the zone center $\Gamma$ move to deeper binding energies and an electron pocket appears instead. The overall band renormalization remains basically the same throughout the doping range we studied, suggesting that the local magnetic/electronic correlations are not affected by carrier doping. We speculate that a balance between itinerant properties of mobile carriers and local interactions may play an important role for the superconductivity.

View original: http://arxiv.org/abs/1206.4402