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arXiv · 1106.2643

Softening of the Bond-Stretching Phonon of Ba1-xKxBiO3 at the Metal to Insulator Transition

H. Khosroabadi·S. Miyasaka·J. Kobayashi·K. Tanaka·H. Uchiyama·A. Q. R. Baron·S. Tajima
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Abstract

The dispersion of phonons in Ba1-xKxBiO3 along the (3+q, 0, 0) direction in reciprocal space was determined for x=0, 0.30, 0.37, 0.52 using high-resolution inelastic X-ray scattering. The observed phonon energies near Γwere in good agreement with published optical data. It was found that two high-energy modes strongly soften near q=0.25 when the system becomes metallic (x >0.35). There was no softening in the insulating phase, even at x=0.30, very near the metal-insulator transition. This suggests that the phonon softening is linked to the appearance of the Fermi-surface.

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H. Khosroabadi, S. Miyasaka, J. Kobayashi, K. Tanaka, H. Uchiyama, A. Q. R. Baron, S. Tajima. 2011-06-14. Softening of the Bond-Stretching Phonon of Ba1-xKxBiO3 at the Metal to Insulator Transition. https://doi.org/10.1103/physrevb.83.224525

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