Lattice dynamics of the cluster chain compounds M2Mo6Se6 (M = K, Rb, Cs, In, and Tl)
Howard, Christopher A.
Petrovic, Alexander Paul
Date of Issue2018
School of Physical and Mathematical Sciences
The lattice dynamics of members of the M2Mo6Se6 family of materials with guest ions M = K, Rb, Cs, In, and Tl has been studied using inelastic x-ray scattering and Raman spectroscopy at room temperature, as well as by ab initio calculations. We find a good match between calculations and experiment, both for structure factors (eigenvectors) and for the calculated phonon frequencies. The observed lattice dynamics for Tl2Mo6Se6 show no signs of anharmonicity or absence of avoided dispersion crossings, thus ruling out previously hypothesized rattling phonon modes. The reduced mode energies for In2Mo6Se6 are identified as only partially responsible for the lower superconducting transition temperature Tc in this material when compared to Tl2Mo6Se6.
Physical Review B
© 2018 American Physical Society. This paper was published in Physical Review B and is made available as an electronic reprint (preprint) with permission of American Physical Society. The published version is available at: [http://dx.doi.org/10.1103/PhysRevB.98.014104]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.