Disordered LTT structural ground state in La2-xBaxCuO4

Abstract

The local structural ground state of La_2-xBa_xCuO4 has been determined by polarized x-ray absorption fine structure (XAFS) spectroscopy at all three Cu, La and Ba K-edges for x=0.125, 0.15 at T=10K. The combined data reveal a disordered low temperature tetragonal (LTT) ground state, with Ba-induced disorder extending as far as 5 Åand resulting in a different tilt configuration of the CuO6 octahedra near the dopant sites. The role of dopant-induced disorder in determining the structural ground state is discussed and compared to the closely related La_2-xSr_xCuO4 system. The local tilt angle of the CuO6 octahedra, √ < θ^2 >, averaged over all Cu sites is found to be ≈ 2 < θ>, with <θ> being the long-range-averaged tilt angle measured by diffraction techniques. This result favors a density of states effect being at the basis of Tc suppression for x=0.125.

Department(s)

Materials Science and Engineering

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 American Physical Society, All rights reserved

Publication Date

1998-03-01

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