Soft Phonons and Structural Phase Transition in Superconducting Ba0.59K0.41BiO3

Published

March 3, 2011

Author(s)

Hye J. Kang, Y. S. Lee, Jeffrey W. Lynn, S. V. Shiryaev, S.N. Barilo

Abstract

We have observed a softening of phonons and a structural phase transition in a superconducting Ba_0.6K_0.4BiO₃ (Tc = 31 K) single crystal using elastic and inelastic neutron scattering measurements. The soft phonon occurs for the [111] transverse acoustic mode at the zone boundary. The phonon energies in this vicinity are found to continuously decrease with decreasing temperature from above room temperature to 200 K, where a structural phase transition from cubic to tetragonal symmetry occurs. The overall results are consistent with previous data that reported phonon softening and a (0.5, 0.5, 0.5) type superstructure in several Ba_1-xK_xBiO₃ systems. However, we also find weak (0.5, 0.5, 0) type superstructure peaks that reveal an additional component to the modulation. No significant change related to the superconductivity was observed for the soft phonon energies or linewidths.

Citation

Physica C-Superconductivity and Its Applications

Volume

471

Pub Type

Journals

Download Paper

Local Download

Keywords

Electron-phonon interaction, superconductivity, inelastic neutron scattering, soft phonon, structural phase transition, BKBO, Ba-KBiO3

Citation

Kang, H. , Lee, Y. , Lynn, J. , Shiryaev, S. and Barilo, S. (2011), Soft Phonons and Structural Phase Transition in Superconducting Ba_0.59K_0.41BiO₃, Physica C-Superconductivity and Its Applications, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906300 (Accessed April 26, 2024)