English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We systematically demonstrate the temperature-dependent thermal transportproperties in crystalline Ge$_2$Sb$_2$Te$_5$via first-principles densityfunctional theory-informed linearized Boltzmann transport equation. Theinvestigation, covering a wide temperature range (30 K-600 K), reports theemergence of an unusual optical phonon-dominated thermal transport incrystalline Ge$_2$Sb$_2$Te$_5$. Further, a significant contribution offour-phonon scattering is recorded which markedly alters the lattice thermalconductivity. Therefore, the combined effect of cubic and quartic phononanharmonicity is seen to navigate the underlying physical mechanism and open upintriguing phononic interactions in Ge$_2$Sb$_2$Te$_5$ at high temperature.Irrespective of three and four-phonon processes, Umklapp is seen to prevailover normal scattering events. Consequently, four-phonon scattering is found tonotably reduce the lattice thermal conductivity of Ge$_2$Sb$_2$Te$_5$ to 28$\%$ at room temperature and 42 $\%$ at higher temperature. This quarticanharmonicity further manifests in the breakdown of T$^{-1}$ scaling of thermalconductivity and challenges the idea of a universal lower bound to phononicthermal diffusivity at high temperature. The faster decay of thermaldiffusivity compared to T$^{-1}$ is rationalized encompassing the quarticanharmonicity via a modified time scale. These results invoke betterunderstanding and precision to the theoretical prediction of thermal transportproperties of Ge$_2$Sb$_2$Te$_5$. Concomitantly, this also triggers thepossibility to explore the manifestations of the lower bound of thermaldiffusivity in materials possessing pronounced four-phonon scattering.

Significant four-phonon scattering and its heat transfer implications in crystalline Ge$_2$Sb$_2$Te$_5$