As-75 NQR signature of the isoelectronic nature of ruthenium for iron substitution in LaFe1-xRuxAsO

作者：Mazzani Marcello^*; Bonfa Pietro; Allodi Giuseppe; Sanna Samuele; Martinelli Alberto; Palenzona Andrea; Manfrinetti Pietro; Putti Marina; De Renzi Roberto

来源：Physica Status Solidi (B) Basic Research, 2014, 251(5): 974-979.

DOI：10.1002/pssb.201350237

• DFT calculations
• iron-based superconductors
• nuclear quadrupole resonance
• superconductivity
• strongly correlated electron systems

We have investigated the effects of the isovalent ruthenium substitution in LaFe1-xRuxAsO, by extensive As-75 NQR (nuclear quadrupole resonance) measurements, supported by DFT (density functional theory) calculations, in order to characterize both the lattice and electronic structure details. The evidence for five different local configurations around the arsenic site emerges upon increasing ruthenium for iron substitution. DFT calculations confirm the attribution of the measured electric field gradients (EFGs) to ruthenium atom occupancies (0, 1, 2, 3, and 4) on the nearest-neighbour sites of arsenic. It is found that the low-frequency (Ru-free) NQR peak remains almost unaffected upon ruthenium substitution, providing an experimental confirmation that ruthenium does not introduce delocalized carriers in the iron plane.

• 出版日期2014-5