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arXiv · 0802.2765

Soft-phonon-driven superconductivity in CaAlSi as seen by inelastic x-ray scattering

S. Kuroiwa·A. Q. R. Baron·T. Muranaka·R. Heid·K. -P. Bohnen·J. Akimitsu
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Abstract

Inelastic x-ray scattering and $ab$-$initio$ calculation are applied to investigate the lattice dynamics and electron-phonon coupling of the ternary silicide superconductor CaAlSi ($P/bar{6}m2$). A soft c-axis polarized mode is clearly observed along the $/Gamma$-$A$-$L$ symmetry directions. The soft mode is strongly anharmonically broadened at room temperature, but, at 10 K, its linewidth narrows and becomes in good agreement with calculations of linear electron-phonon coupling. This establishes a coherent description of the detailed phonon properties in this system and links them clearly and consistently with the superconductivity.

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S. Kuroiwa, A. Q. R. Baron, T. Muranaka, R. Heid, K. -P. Bohnen, J. Akimitsu. 2008-03-18. Soft-phonon-driven superconductivity in CaAlSi as seen by inelastic x-ray scattering. https://doi.org/10.1103/physrevb.77.140503

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