Origin of the tetragonal-to-orthorhombic (nematic) phase transition in FeSe: a combined thermodynamic and NMR study

Abstract

The nature of the tetragonal-to-orthorhombic structural transition at $T_s\approx 90$ K in single crystalline FeSe is studied using shear-modulus, heat-capacity, magnetization and NMR measurements. The transition is shown to be accompanied by a large shear-modulus softening, which is practically identical to that of underdoped Ba(Fe,Co)${}_2$As${}_2$, suggesting very similar strength of the electron-lattice coupling. On the other hand, a spin-fluctuation contribution to the spin-lattice relaxation rate is only observed below $T_s$. This indicates that the structural, or "nematic", phase transition in FeSe is not driven by magnetic fluctuations.

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Cited by in corpus (8)

• Iron-Based Superconductors: current status of materials and pairing mechanism
• Emergence of the nematic electronic state in FeSe
• Observation of two distinct $d_{xz}/d_{yz}$ band splittings in FeSe
• The origin of nematic order in FeSe
• Strong $(\pi ,0)$ spin fluctuations in $\beta$-FeSe observed by neutron spectroscopy
• Pressure-induced antiferromagnetic transition and phase diagram in FeSe
• Resistivity and magnetoresistance of FeSe single crystals under Helium-gas pressure
• Orbital Nematic Order and Interplay with Magnetism in the Two-Orbital Hubbard Model