Unveiling the hidden nematicity and spin subsystem in FeSe

Abstract

The nematic order (nematicity) is considered one of the essential ingredients to understand the mechanism of Fe-based superconductivity. In most Fe-based superconductors (pnictides), nematic order is reasonably close to the antiferromagnetic order. In FeSe, in contrast, a nematic order emerges below the structure phase transition at T_s = 90 K with no magnetic order. The case of FeSe is of paramount importance to a universal picture of Fe-based superconductors. The polarized ultrafast spectroscopy provides a tool to probe simultaneously the electronic structure and the magnetic interactions through quasiparticle dynamics. Here we show that this approach reveals both the electronic and magnetic nematicity below and, surprisingly, its fluctuations far above Ts to at least 200 K. The quantitative pump-probe data clearly identify a correlation between the topology of the Fermi surface (FS) and the magnetism in all temperature regimes, thus providing profound insight into the driving factors of nematicity in FeSe and the origin of its uniqueness.

Supplementary Information included

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Cited by in corpus (18)

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• Origin of the density wave instability in trilayer nickelate La${}_4$Ni${}_3$O${}_{10}$ revealed by optical and ultrafast spectroscopy
• Quantitative characterization of short-range orthorhombic fluctuations in FeSe through pair distribution function analysis
• Robust short-range-ordered nematicity in FeSe evidenced by high-pressure NMR
• Photoinduced ultrafast dynamics of local nematicity and lattice distortions in FeSe crystals
• Widespread orthorhombic fluctuations in the (Sr,Na)Fe${}_2$As${}_2$ family of superconductors
• Band structure reconstruction across nematic order in high quality FeSe single crystal as revealed by optical spectroscopy study
• Interplay between nematicity and Bardasis-Schrieffer modes in the short-time dynamics of unconventional superconductors
• Polarization-resolved broadband time-resolved optical spectroscopy for complex materials: application to the case of MoTe${}_2$ polytypes
• Applications for ultimate spatial resolution in LASER based $\mu$-ARPES: A FeSe case study
• Disorder-Induced Electronic Nematicity
• The Hidden Nematic Fluctuations in the Triclinic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 Superconductor Revealed by Ultrafast Optical Spectroscopy
• Nematic response revealed by coherent phonon oscillations in BaFe${}_2$As${}_2$
• Electronic nematic order in the normal state of strontium ruthenate
• Edwards-Anderson parameter and local Ising-nematicity in FeSe revealed via NMR spectral broadening