title: Superconductivity Emerging from an Electronic Phase Separation in the Charge Ordered Phase of RbFe_{2}As_{2}.
abstract: ^{75}As, ^{87}Rb, and ^{85}Rb nuclear quadrupole resonance (NQR) and ^{87}Rb nuclear magnetic resonance measurements in a RbFe_{2}As_{2} iron-based superconductor are presented. We observe a marked broadening of the ^{75}As NQR spectrum below T_{0}≃140  K which is associated with the onset of a charge order in the FeAs planes. Below T_{0} we observe a power-law decrease in the ^{75}As nuclear spin-lattice relaxation rate down to T^{*}≃20  K. Below T^{*} the nuclei start to probe different dynamics owing to the different local electronic configurations induced by the charge order. A fraction of the nuclei probes spin dynamics associated with electrons approaching a localization while another fraction probes activated dynamics possibly associated with a pseudogap. These different trends are discussed in light of an orbital selective behavior expected for the electronic correlations.
authors.affiliation: Department of Physics, University of Pavia-CNISM, I-27100 Pavia, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Civardi
authors.affiliation: Department of Physics, University of Pavia-CNISM, I-27100 Pavia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Moroni
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Babij
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland.
authors.forename: Z
authors.initials: Z
authors.lastname: Bukowski
authors.affiliation: Department of Physics, University of Pavia-CNISM, I-27100 Pavia, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Carretta