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arXiv · 1608.04532

Superconductivity emerging from an electronic phase separation in the charge ordered phase of RbFe$_2$As$_2$

E. Civardi·M. Moroni·M. Babij·Z. Bukowski·P. Carretta
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Abstract

$^{75}$As, $^{87}$Rb and $^{85}$Rb nuclear quadrupole resonance (NQR) and $^{87}$Rb nuclear magnetic resonance (NMR) measurements in RbFe$_2$As$_2$ iron-based superconductor are presented. We observe a marked broadening of $^{75}$As NQR spectrum below $T_0\simeq 140$ 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 $^{75}$As nuclear spin-lattice relaxation rate down to $T^*\simeq 20$ K. Below that temperature 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 the light of an orbital selective behaviour expected for the electronic correlations.

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E. Civardi, M. Moroni, M. Babij, Z. Bukowski, P. Carretta. 2016-10-26. Superconductivity emerging from an electronic phase separation in the charge ordered phase of RbFe$_2$As$_2$. https://doi.org/10.1103/physrevlett.117.217001

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