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arXiv · 1603.04589

Pressure Induced Stripe-order Antiferromagnetism and First-order Phase Transition in FeSe

P. S. Wang·S. S. Sun·Y. Cui·W. H. Song·T. R. Li·Rong Yu·Hechang Lei·Weiqiang Yu
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Abstract

To elucidate the magnetic structure and the origin of the nematicity in FeSe, we perform a high-pressure $^{77}$Se NMR study on FeSe single crystals. We find a suppression of the structural transition temperature with pressure up to about 2 GPa from the anisotropy of the Knight shift. Above 2 GPa, a stripe-order antiferromagnetism that breaks the spatial four-fold rotational symmetry is determined by the NMR spectra under different field orientations and with temperatures down to 50 mK. The magnetic phase transition is revealed to be first-order type, implying the existence of a concomitant structural transition via a spin-lattice coupling. Stripe-type spin fluctuations are observed at high temperatures, and remain strong with pressure. These results provide clear evidences for strong coupling between nematicity and magnetism in FeSe, and therefore support a universal scenario of magnetic driven nematicity in iron-based superconductors.

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P. S. Wang, S. S. Sun, Y. Cui, W. H. Song, T. R. Li, Rong Yu, Hechang Lei, Weiqiang Yu. 2016-11-10. Pressure Induced Stripe-order Antiferromagnetism and First-order Phase Transition in FeSe. https://doi.org/10.1103/physrevlett.117.237001

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