Itinerancy-enhanced quantum fluctuation of magnetic moments in iron-based superconductors.

نویسندگان

  • Yu-Ting Tam
  • Dao-Xin Yao
  • Wei Ku
چکیده

We investigate the influence of itinerant carriers on the dynamics and fluctuation of local moments in Fe-based superconductors, via linear spin-wave analysis of a spin-fermion model containing both itinerant and local degrees of freedom. Surprisingly, against the common lore, instead of enhancing the (π,0) order, itinerant carriers with well-nested Fermi surfaces are found to induce a significant amount of spatial and temporal quantum fluctuation that leads to the observed small ordered moment. Interestingly, the underlying mechanism is shown to be an intrapocket nesting-associated long-range coupling rather than the previously believed ferromagnetic double-exchange effect. This challenges the validity of ferromagnetically compensated first-neighbor coupling reported from short-range fitting to the experimental dispersion, which turns out to result instead from the ferro-orbital order that is also found instrumental in stabilizing the magnetic order.

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عنوان ژورنال:
  • Physical review letters

دوره 115 11  شماره 

صفحات  -

تاریخ انتشار 2015