Nematicity and magnetism in LaFeAsO single crystals probed by ${}^{75}$As nuclear magnetic resonance

Abstract

We report a ${}^{75}$As nuclear magnetic resonance study in LaFeAsO single crystals, which undergoes nematic and antiferromagnetic transitions at $T_{\text{nem}}\sim 156$ K and $T_N\sim 138$ K, respectively. Below $T_{\text{nem}}$, the ${}^{75}$As spectrum splits sharply into two for an external magnetic field parallel to the orthorhombic $a$ or $b$ axis in the FeAs planes. Our analysis of the data demonstrates that the NMR line splitting arises from an electronically driven rotational symmetry breaking. The ${}^{75}$As spin-lattice relaxation rate as a function of temperature shows that spin fluctuations are strongly enhanced just below $T_{\text{nem}}$. These NMR findings indicate that nematic order promotes spin fluctuations in magnetically ordered LaFeAsO, as observed in non-magnetic and superconducting FeSe. We conclude that the origin of nematicity is identical in both FeSe and LaFeAsO regardless of whether or not a long range magnetic order develops in the nematic state.

5 pages, 4 figures, published as a rapid communication in PRB

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Cited by in corpus (8)

• Separate tuning of nematicity and spin fluctuations to unravel the origin of superconductivity in FeSe
• Singular magnetic anisotropy in the nematic phase of FeSe
• Charge and nematic orders in AFe${}_2$As${}_2$ (A= Rb,Cs) superconductors
• A unified phase diagram of F-doped LaFeAsO by means of NMR and NQR parameters
• Strain-derivative of thermoelectric properties: a sensitive probe for nematicity
• Mapping out the spin fluctuations in Co-doped LaFeAsO single crystals by NMR
• Microscopic phase diagram of LaFeAsO single crystals under pressure
• Nematicity in LaFeAsO single crystals studied by elastoresistance, high-resolution thermal expansion and shear-modulus measurements