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

Phonon scattering calculations predict the drag force acting on defects anddislocations rises linearly with temperature, in direct contradiction withmolecular dynamics simulations that often finds the drag force to beindependent of temperature. Using the Mori-Zwanzig projection technique, withno recourse to elasticity or scattering theories, we derive a general Langevinequation for a crystal defect, with full treatment of discreteness andnon-linearity in the defect core. We obtain an analytical expression for thedrag force that is evaluated in molecular statics and molecular dynamics,extracting the force on a defect directly from the inter-atomic forces. Ourresults show that a temperature independent drag force arises becausevibrations in a discrete crystal are never independent of the defect motion, animplicit assumption in any phonon-based approach. This effect remains even whenthe Peierls barrier is effectively zero, invalidating qualitative explanationsinvolving the radiation of phonons. We apply our methods to an interstitialdefect in tungsten and solitons in the Frenkel-Kontorova model, finding verygood agreement with trajectory-based estimations of the thermal drag force.

The phonon drag force acting on a mobile crystal defect: full treatment of discreteness and non-linearity