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

Author(s)

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

Abstract

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(s)

Department of Mineralogy and Crystallography

External organisation(s)

Jacobs Universität Bremen

Journal

Journal of Materials Science

Volume

55

Pages

177-190

No. of pages

14

ISSN

0022-2461

DOI

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

Publication date

03-2020

Peer reviewed

Yes

Austrian Fields of Science 2012

104011 Materials chemistry, 105113 Crystallography

Keywords

ASJC Scopus subject areas

Mechanics of Materials, Mechanical Engineering, Materials Science(all)

Portal url

https://ucris.univie.ac.at/portal/en/publications/uniaxial-negative-thermal-expansion-in-the-mullite-and-boraxtype-pbalbo4-polymorphs(b9290d26-fc83-45f5-8ba7-95b6773638f8).html