Anomalous lattice specific heat and rattling phonon modes in quadruple perovskites

Valentin Yu. Irkhin; Zhehong Liu; Danil A. Myakotnikov; Evgenia V. Komleva; Youwen Long; Sergey V. Streltsov

doi:10.1016/j.solidstatesciences.2025.108187

paper

Anomalous lattice specific heat and rattling phonon modes in quadruple perovskites

arXiv:2512.19384 · doi:10.1016/j.solidstatesciences.2025.108187

Abstract

Experimental data on the specific heat $C_{p}$ of quadruple perovskites ACu $_{3}$ Fe $_{2}$ Re $_{2}$ O $_{12}$ (A = Mn, Cu, La, Ce, Dy) are presented, demonstrating an anomalous concave-down $C_{p} / T$ vs. $T^{2}$ curve and a bell-shaped feature in $β (T) = (C_{p} - γ T) / T^{3}$ plotted against $T$ on a logarithmic scale. This feature is most pronounced for A = Cu and Mn. These findings can be explained by the rattling phenomenon, previously identified in other systems such as filled skutterudites and $β$ -pyrochlores. Using first-principles DFT+U calculations, the presence of a rattling mode in A = Mn system is directly confirmed. A qualitative interpretation of the rattling mechanism in terms of a pseudo-Jahn-Teller effect is proposed.

arXiv comment8 pages

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