Doping dependence of spin fluctuations and electron correlations in iron pnictides

0352183 - FZÚ 2011 RIV US eng J - Journal Article
Ikeda, H. - Arita, R. - Kuneš, Jan
Doping dependence of spin fluctuations and electron correlations in iron pnictides.
Physical Review. B. Roč. 82, č. 2 (2010), 024508/1-024508/6. ISSN 1098-0121
Institutional research plan: CEZ:AV0Z10100521
Keywords : iron pnicitdes * dynamic spin susceptibility * fluctuation-exchange approximation
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.772, year: 2010
http://prb.aps.org/abstract/PRB/v82/i2/e024508

Doping dependence of the spin fluctuations and the electron correlations in the effective five-band Hubbard model for iron pnictides is investigated using the fluctuation-exchange approximation. For a moderate hole doping, we find a dominant low-energy spin excitation at Q=(Π,0) which becomes critical at low temperature. The low-energy spin excitations in the heavily hole-doped region are characterized by weak Q dependence. The electron doping leads to an appearance of a pseudogap in spin-excitation spectrum. Correspondingly, the NMR-1/T1 relaxation rate is strongly enhanced on the hole-doped side and suppressed on the electron-doped side of the phase diagram. This behavior can be to large extent understood by systematic changes of the Fermi-surface topology.
Permanent Link: http://hdl.handle.net/11104/0191757