Nematic Fluctuations and Phase Transitions in LaFeAsO: a Raman Scattering Study

Abstract

Raman scattering experiments on LaFeAsO with splitted antiferromagnetic (T_AFM = 140 K) and tetragonal-orthorhombic (T_S = 155 K) transitions show a quasi-elastic peak (QEP) in B2g symmetry (2 Fe tetragonal cell) that fades away below ~T_AFM and is ascribed to electronic nematic fluctuations. A scaling of the reported shear modulus with the T-dependence of the QEP height rather than the QEP area indicates that magnetic degrees of freedom drive the structural transition. The large separation between T_S and T_AFM in LaFeAsO compared with their coincidence in BaFe2As2 manifests itself in slower dynamics of nematic fluctuations in the former.

8 pages, 9 figures

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Cited by in corpus (7)

• Elastoresistance measurements on CaKFe${}_4$As${}_4$ and KCa${}_2$Fe${}_4$As${}_4$F${}_2$ with the Fe site of $C_{2v}$ symmetry
• Intertwined spin-orbital coupled orders in the iron-based superconductors
• Fluctuations and pairing in Fe-based superconductors: Light scattering experiments
• Anomalous magneto-elastic coupling in Au-doped BaFe2As2
• Magneto-elastic coupling in Fe-based superconductors
• Superconducting gap and nematic resonance at the quantum critical point observed by Raman scattering in $\mathrm{BaF}{\mathrm{e}}_2({\mathrm{As}}_{1-x}{\mathrm{P}}_x{)}_2$
• Possible signature of broken symmetry state near the quantum critical point in P doped BaFe${}_2$As${}_2$: A Raman spectroscopy study