Hu, YuwenRen, XiaoZhang, RuiLuo, HuiqianKasahara, ShigeruWatashige, TatsuyaShibauchi, TakasadaDai, PengchengZhang, YanMatsuda, YujiLi, Yuan2017-05-232017-05-232016Hu, Yuwen, Ren, Xiao, Zhang, Rui, et al.. "Nematic magnetoelastic effect contrasted between Ba(Fe1−xCox)2As2 and FeSe." <i>Physical Review B,</i> 93, no. 6 (2016) American Physical Society: https://doi.org/10.1103/PhysRevB.93.060504.https://hdl.handle.net/1911/94366To elucidate the origin of nematic order in Fe-based superconductors, we report a Raman scattering study of lattice dynamics, which quantify the extent of C4-symmetry breaking, in BaFe2As2 and FeSe. FeSe possesses a nematic ordering temperature Ts and orbital-related band-energy split below Ts that are similar to those in BaFe2As2, but unlike BaFe2As2 it has no long-range magnetic order. We find that the Eg phonon-energy split in FeSe becomes substantial only well below Ts, and its saturated value is much smaller than that in BaFe2As2. Together with reported results for the Ba(Fe1−xCox)2As2 family, the data suggest that magnetism exerts a major influence on the lattice.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttps://doi.org/10.1103/PhysRevB.93.060504