Abstract
The nature of the tetragonal-to-orthorhombic structural transition at in single crystalline FeSe is studied using shear-modulus, heat-capacity, magnetization, and nuclear magnetic resonance measurements. The transition is shown to be accompanied by a large shear-modulus softening, which is practically identical to that of underdoped , suggesting a 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 . This indicates that the structural, or “nematic,” phase transition in FeSe is not driven by magnetic fluctuations.
- Received 21 July 2014
DOI:https://doi.org/10.1103/PhysRevLett.114.027001
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