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arXiv · 1808.08183

Paramagnon dispersion in $\beta$-FeSe observed by Fe $L$-edge resonant inelastic x-ray scattering

M. C. Rahn·K. Kummer·N. B. Brookes·A. A. Haghighirad·K. Gilmore·A. T. Boothroyd
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Abstract

We report an Fe $L$-edge resonant inelastic x-ray scattering (RIXS) study of the unusual superconductor $\beta$-FeSe. The high energy resolution of this RIXS experiment ($\approx\,$55$\,$meV FWHM) made it possible to resolve low-energy excitations of the Fe $3d$ manifold. These include a broad peak which shows dispersive trends between 100-200$\,$meV along the $(\pi,0)$ and $(\pi,\pi)$ directions of the one-Fe square reciprocal lattice, and which can be attributed to paramagnon excitations. The multi-band valence state of FeSe is among the most metallic in which such excitations have been discerned by soft x-ray RIXS.

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M. C. Rahn, K. Kummer, N. B. Brookes, A. A. Haghighirad, K. Gilmore, A. T. Boothroyd. 2018-08-24. Paramagnon dispersion in $\beta$-FeSe observed by Fe $L$-edge resonant inelastic x-ray scattering. https://doi.org/10.1103/physrevb.99.014505

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