Suppression of Three-Dimensional Charge Density Wave Ordering via Thickness Control

Abstract

Barium bismuth oxide (BaBiO 3 ) is the end member of two families of high-T c superconductors, i.e., BaPb 1−x Bi x O 3 and Ba 1−x K x BiO 3 . The undoped parent compound is an insulator, exhibiting a charge density wave that is strongly linked to a static breathing distortion in the oxygen sublattice of the perovskite structure. We report a comprehensive spectroscopic and x-ray diffraction study of BaBiO 3 thin films, showing that the minimum film thickness required to stabilize the breathing distortion and charge density wave is ≈11 unit cells, and that both phenomena are suppressed in thinner films. Our results constitute the first experimental observation of charge density wave suppression in bismuthate compounds without intentionally introducing dopants. © 2015 American Physical Society. (c)2015 American Physical society