Correlated band structure of superconducting NdFeAsO$_{0.9}$F$_{0.1}$: dynamical mean-field study

In this Letter we report the LDA+DMFT (method combining local density approximation with dynamical mean-field theory) results for spectral properties of the superconductor NdFeAsO$_{0.9}$F$_{0.1}$ in the paramagnetic phase. The calculated momentum-resolved spectral functions are in good agreement with angle-resolved photoemission spectra (ARPES). The obtained effective quasiparticle mass enhancement ($m^{*}/m=1.4$) is smaller than the one in isostructural parent compound LaFeAsO which critical temperature under the same fluorine doping (LaFeAsO$_{0.9}$F$_{0.1}$) is two times lower. Our results demonstrate that in quaternary FeAs-based superconductors of the same class, changes of the crystal structure caused by substitution of one rare-earth atom, implicitly result in reduction of the electronic correlation strength.