Uniaxial negative thermal expansion in the mullite- and borax-type PbAlBO₄ polymorphs

Autor(en)

Mathias Gogolin, M. Mangir Murshed, Martin Ende, Ronald Miletich, Thorsten M. Gesing

Abstrakt

This study presents an investigation on the axial negative thermal expansion of α-PbAlBO4 and β-PbAlBO4. Polycrystalline and single-crystal samples were prepared by solid-state synthesis method, characterized by temperature- and pressure-dependent X-ray and neutron diffraction experiments. The axial negative linear compressibility (NLC) is known for the α-polymorph, although structurally different the β-polymorph also shows similar NLC phenomenon. The lattice thermal expansion was described using the first-order Grüneisen equation of state, where the vibrational energy was calculated using the Debye–Einstein-Anharmonicity model. The density functional theory (DFT)-based phonon density of states and Raman spectra helped to choose the characteristic frequency to model the metric parameters. Lattice thermal expansion was additionally simulated in the quasi-harmonic approximation using the plane-wave DFT approach at the PBEsol level. The apparent departure of the quasi-harmonic approximation model has been discussed in terms of associated thermodynamic functions. The interplay between the topology-induced negative cross-compliance and anisotropic Grüneisen parameter has been identified as the driving force for the axial negative linear compressibility and axial negative thermal expansion.

Organisation(en)

Institut für Mineralogie und Kristallographie

Externe Organisation(en)

Jacobs Universität Bremen

Journal

Journal of Materials Science

Band

55

Seiten

177-190

Anzahl der Seiten

14

ISSN

0022-2461

DOI

https://doi.org/10.1007/s10853-019-04013-6

Publikationsdatum

03-2020

Peer-reviewed

Ja

ÖFOS 2012

104011 Materialchemie, 105113 Kristallographie

Schlagwörter

ASJC Scopus Sachgebiete

Mechanics of Materials, Mechanical Engineering, Allgemeine Materialwissenschaften

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/b9290d26-fc83-45f5-8ba7-95b6773638f8