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

One of the unique properties of graphene is its extremely high mechanicalstrength. Several studies have shown that the mechanical failure of graphenesheet under a tensile strain is due to the enhancement of the Kohn anomaly ofthe zone boundary transverse optical phonon modes. In this work, we derive ananalytical expression of the Kohn anomaly parameter $\alpha_{\vec{K}}$ of thesephonons in graphene deformed by a uniaxial strain along the armchair direction.We show that, the tilt of Dirac cones, induced by the strain, contributes tothe enhancement of the Kohn anomaly under a tensile deformation and gives riseto a dominant contribution of the so-called {\it outer} intervalley mediatedphonon processes. Moreover, the Kohn anomaly is found to be anisotropic withrespect to the phonon wave vectors around the K point. This anisotropy may beat the origin of the light polarization dependence of the Raman 2D band of thestrained graphene. Our results uncover, not only, the role of the Kohn anomalyin the anisotropic mechanical failure of the graphene sheet, under strainsapplied along the armchair and zigzag directions, but shed also light on thedoping induced strengthening of strained graphene.

Kohn anomaly of optical zone boundary phonons in uniaxial strained graphene: role of the electronic band structure