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

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.

Has been accepted for publication in Phys Rev B (2011)

References in corpus (1)

• Bond stretching phonon softening and angle-resolved photoemission kinks in optimally doped Bi2Sr1.6La0.4Cu2O6 superconductors

Cited by in corpus (3)

• Correlation-enhanced electron-phonon coupling: Applications of GW and screened hybrid functional to bismuthates, chloronitrides, and other high Tc superconductors
• A hybrid Monte Carlo study of bond-stretching electron-phonon interactions and charge order in BaBiO${}_3$
• Superconducting properties of under- and over-doped Ba${}_x$K${}_{1-x}$BiO${}_3$ perovskite oxide