Itinerancy enhanced quantum fluctuation of magnetic moments in iron-based superconductors
| Autor: | Tam, Yu-Ting, Yao, Dao-Xin, Ku, Wei |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 115, 117001 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.115.117001 |
| Popis: | We investigate the influence of itinerant carriers on 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 ($\pi$,0) order, itinerant carriers with well nested Fermi surfaces is found to induce significant amount of \textit{spatial} and temporal quantum fluctuation that leads to the observed small ordered moment. Interestingly, the underlying mechanism is shown to be intra-pocket 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. Comment: 6 pages, 3 figures, submitted to Phys. Rev. Lett. on 17 September 2014 |
| Databáze: | arXiv |
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