TY - JOUR
T1 - Theory of two-magnon Raman scattering in alkaline iron selenide superconductors
AU - Liu, C. S.
AU - Zhang, A. M.
AU - Xu, T. F.
AU - Wu, W. C.
N1 - Funding Information:
We are grateful to Prof. Qingming Zhang for many useful comments. This work was supported by the Hebei Provincial Natural Science Foundation of China (Grant Nos. A2010001116 and A2012203174 ), National Natural Science Foundation of China (Grant Nos. 10974169 and 11304270 ), the Ministry of Science and Technology of China (973 Projects: 2011CBA00112 and 2012CB921701), the Fundamental Research Funds for the Central Universities, the Research Funds of Renmin University of China , and the Ministry of Science and Technology, Taiwan (Grant No. NSC 99-2112-M-003-006-MY3 ).
Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.
PY - 2014/11/15
Y1 - 2014/11/15
N2 - Motivated by the recent experiment of two-magnon Raman scattering in alkaline iron selenide superconductors (Zhang et al., 2012), we investigate in details the underlying spin interactions of the 5×5 antiferromagnetic superstructure. Based on the linear spin wave approximation, the Fleury-London (FL) two-magnon Raman cross-sections are calculated. By comparing theoretical results with the Raman data in both Ag and Bg channels, an optimal set of exchange parameters which are consistent with the fitting to the neutron scattering data are obtained. It reveals that the experimentally observed broad and asymmetric peaks around 1600 cm-1 are dominantly originated from quasiparticle excitations in two nearly degenerate magnon bands in the (0,±π) and (±π,0) directions. The result thus supports that the magnetic properties in alkaline iron selenide AFe1.6+xSe6 superconductors can be basically described by the quantum spin model with up to third nearest-neighbor exchange couplings.
AB - Motivated by the recent experiment of two-magnon Raman scattering in alkaline iron selenide superconductors (Zhang et al., 2012), we investigate in details the underlying spin interactions of the 5×5 antiferromagnetic superstructure. Based on the linear spin wave approximation, the Fleury-London (FL) two-magnon Raman cross-sections are calculated. By comparing theoretical results with the Raman data in both Ag and Bg channels, an optimal set of exchange parameters which are consistent with the fitting to the neutron scattering data are obtained. It reveals that the experimentally observed broad and asymmetric peaks around 1600 cm-1 are dominantly originated from quasiparticle excitations in two nearly degenerate magnon bands in the (0,±π) and (±π,0) directions. The result thus supports that the magnetic properties in alkaline iron selenide AFe1.6+xSe6 superconductors can be basically described by the quantum spin model with up to third nearest-neighbor exchange couplings.
KW - Alkaline iron selenide superconductors
KW - Spin-wave theory
KW - Two-magnon Raman scattering
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U2 - 10.1016/j.physc.2014.08.008
DO - 10.1016/j.physc.2014.08.008
M3 - Article
AN - SCOPUS:84907714383
SN - 0921-4534
VL - 506
SP - 76
EP - 82
JO - Physica C: Superconductivity and its applications
JF - Physica C: Superconductivity and its applications
ER -