Senn Group investigation of structural phase transitions in a series of cuprate RP oxides has identified the effect that single-ion anisotropy, associated with the concentration of JT-active sites, has on the structural transition temperature in the high-Tc superconducting cuprates.

"Interplay between Jahn–Teller Distortions and Structural Phase Transitions in Ruddlesden–Poppers"

Anna HerlihyWei-Tin ChenClemens RitterYu-Chun ChuangMark S. Senn*

First published: 18 February 2025: https://doi.org/10.1021/jacs.5c00459

Abstract

The interplay between crystallographic symmetry, structural distortions, and the tolerance factor derived from the isotropic ionic radii of the constituent cations and anions of inorganic perovskites and related materials is a ubiquitous concept in solid-state and materials chemistry. Here we demonstrate a model for the phase transition temperatures associated with these structural distortions in layered perovskites by considering the anisotropy associated with cations, which are susceptible to first-order Jahn–Teller distortions. These symmetry-lowering phase transitions are known to have a significant interplay with superconductivity in the high-TC layered cuprates, and untangling the chemistry that can effectively control them is of the utmost relevance in the search for similar phenomena in the nickelates, the study of which has been greatly stimulated by recent reports of high-pressure superconductivity.