Browsing by Author "Zhang, W.-L."

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    In-plane electronic anisotropy resulted from ordered magnetic moment in iron-based superconductors
    (American Physical Society, 2020) Wu, S.-F.; Zhang, W.-L.; Thorsmølle, V.K.; Chen, G.F.; Tan, G.T.; Dai, P.C.; Shi, Y.G.; Jin, C.Q.; Shibauchi, T.; Kasahara, S.; Matsuda, Y.; Sefat, A.S.; Ding, H.; Richard, P.; Blumberg, G.
    We study the in-plane electronic anisotropy in the parent compounds of several families of Fe-based superconductors (BaFe2As2, EuFe2As2, NaFeAs, LiFeAs, FeSe, and LaFeAsO) by polarization-resolved Raman scattering. We measure intensity of the fully symmetric c-axis vibration of As atom mode in the XY scattering geometry and notice that the mode's intensity is significantly enhanced below the magnetostructural transition only for compounds showing magnetic ordering. In particular, we find that the intensity ratio of this As phonon in the XY vs. XX scattering geometries is proportional to the square of the ordered magnetic moment. We relate this As phonon intensity enhancement below the Néel temperature in iron pnictides to in-plane electronic anisotropy induced by the collinear spin-density wave order.
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    Raman scattering study of NaFe0.53Cu0.47As
    (American Physical Society, 2018) Zhang, W.-L.; Song, Y.; Wang, W.-Y.; Cao, C.-D.; Dai, P.-C.; Jin, C.-Q.; Blumberg, G.
    We use polarization-resolved Raman scattering to study lattice dynamics in NaFe0.53Cu0.47As single crystals. We identify four A1g phonon modes, at 126, 172, 183, and 197 cm−1, and four B3g phonon modes at 101, 139, 173, and 226 cm−1(D4h point group). The phonon spectra are consistent with the Ibam space group, which confirms that the Cu and Fe atoms form a stripe order. The temperature dependence of the phonon spectra suggests weak electron-phonon and magnetoelastic interactions.