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

Achieving high valley degeneracy (i.e. "band convergence") in a materialusually results in considerably enhanced thermoelectric properties. However, itis still unclear why this strategy of designing efficient thermoelectricmaterials is so successful, since the benefit of increased density of statesmay be severely degraded by intervalley scattering. Using first-principlescalculations, we investigate these effects in $p$-type PbTe, where temperatureinduces alignment of the $L$ and $\Sigma$ valleys at $\sim$~620~K. Weexplicitly show that the thermoelectric power factor and figure of merit peaknear the band convergence temperature. The figure of merit maximum is largerthan those of the individual $L$ and $\Sigma$ valleys. Surprisingly,intervalley scattering does not considerably affect the figure of merit nearthe band convergence temperature and optimal doping conditions, although itreduces the power factor by almost a factor of 2. Our results suggest that bandconvergence will significantly increase the figure of merit if intervalleyscattering is roughly proportional to the density of states and the latticethermal conductivity is considerably lower than the electronic thermalconductivity, even if intervalley scattering is strong.

Temperature induced band convergence, intervalley scattering and thermoelectric transport in p-type PbTe