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arXiv · 1512.00782

Strain-activated structural anisotropy in BaFe2As2

Xiang Chen·Leland Harriger·Athena Sefat·R. J. Birgeneau·Stephen D. Wilson
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Abstract

High-resolution single crystal neutron diffraction measurements are presented probing the magnetostructural response to uniaxial pressure in the iron pnictide parent system BaFe2As2. Scattering data reveal a strain-activated, anisotropic broadening of nuclear Bragg reflections, which increases upon cooling below the resolvable onset of global orthorhombicity. This anisotropy in lattice coherence continues to diverge until a lower temperature scale---the first-order onset of antiferromagnetism---is reached. Our data suggest that antiferromagnetism and strong magnetoelastic coupling drive the strain-activated lattice response in this material and that the development of anisotropic lattice coherence under strain is the physical origin for the anomalous nematic anisotropy in this compound.

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Xiang Chen, Leland Harriger, Athena Sefat, R. J. Birgeneau, Stephen D. Wilson. 2016-03-26. Strain-activated structural anisotropy in BaFe2As2. https://doi.org/10.1103/physrevb.93.144118

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