Microscopic Model Extension for Lattice Thermal Expansion up to Phase‐Transition Temperature

An extension of the Debye–Einstein–anharmonicity (DEA) model has been addressed to describe the lattice thermal expansion up to a temperature‐dependent phase transition. By using an intrinsic anharmonicity (A) term in the DEA model only, it is not possible to describe the continuous changes of the lattice thermal expansion leading to anomalies originating from second‐order phase transitions. Therefore, an extended formalism is empirically developed to model these anomalies of the lattice thermal expansion based on temperature‐dependent X‐ray powder diffraction data. Inspired by Landau's theory of second‐order phase transitions, a gliding function (G) that considers the excess energy above the DEA terms, necessary to drive the phase transition, is introduced. The G‐function has been considered as an additive constituent of the DEA model, leading to the DEA + G model that describes the temperature‐dependent internal energy of the unit cell implemented in the first‐order Mie‐Grüneisen zero pressure equation of state (MG‐EoS). The extended approach allows to describe the soft‐mode‐driven anharmonic internal energy contribution and to determine the critical temperature of both nuclear and magnetic phase transitions.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Microscopic Model Extension for Lattice Thermal Expansion up to Phase‐Transition Temperature ; day:06 ; month:01 ; year:2025 ; extent:9 ; Physica status solidi / B. B, Basic solid state physics ; (06.01.2025) (gesamt 9)

Contributors, Places and Time

• Creator: Gesing, Thorsten M. ; Robben, Lars ; Murshed, M. Mangir

Further information

• DOI: 10.1002/pssb.202400511
• URN: urn:nbn:de:101:1-2501061321151.456467255437
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:32 AM CEST