Theory of two-magnon Raman scattering in alkaline iron selenide superconductors

C. S. Liu, A. M. Zhang, T. F. Xu, Wen-Chin Wu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)76-82
Number of pages7
JournalPhysica C: Superconductivity and its applications
Volume506
DOIs
Publication statusPublished - 2014 Nov 15

Fingerprint

selenides
Superconducting materials
Raman scattering
Iron
Raman spectra
iron
Exchange coupling
Spin waves
Neutron scattering
magnons
Magnetic properties
neutron scattering
magnetic properties
cross sections
approximation
excitation
Experiments
interactions
Direction compound

Keywords

  • Alkaline iron selenide superconductors
  • Spin-wave theory
  • Two-magnon Raman scattering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

Cite this

Theory of two-magnon Raman scattering in alkaline iron selenide superconductors. / Liu, C. S.; Zhang, A. M.; Xu, T. F.; Wu, Wen-Chin.

In: Physica C: Superconductivity and its applications, Vol. 506, 15.11.2014, p. 76-82.

Research output: Contribution to journalArticle

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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.

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