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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In this work, we study thermal conductivity (k) of BC5, an ultra-harddiamondlike semiconductor material, using first-principles computations andanalyze the effect of both isotopic disorder as well as length scaledependence. k of isotopically pure BC5 is computed to be 169 Wm- 1K-1 (alonga-axis) at 300K; this high k is found to be due to the high frequencies andphonon group velocities of both acoustic and optical phonons owing to the lightatomic mass of Carbon (C) and Boron (B) atoms and strong C-C and B-C bonds. Wealso observe a dominance of optical phonons (~ 54%) over acoustic phonons inheat conduction at higher temperatures (~500 K). This unusually highcontribution of optical phonons is found to be due to a unique effect in BC5related to a weaker temperature dependence of optical phonon scattering ratesrelative to acoustic phonons. The effect is explained in terms of highfrequencies of optical phonons causing decay into other high frequency phonons,where low phonon populations cause the decay term to become insensitive totemperature. The effect further leads to high nanoscale thermal conductivity of77 Wm-1K-1 at 100 nm length scale due to optical phonon meanfreepaths being innanometer regime. These results provide avenues for application of BC5 innanoscale thermal management.

Ultrahard BC5 -- an efficient nanoscale heat conductor through dominant contribution of optical phonons