Dominant Phonon Wavevectors and Strain-induced Splitting of the 2D Graphene Raman Mode

Autor:	Narula, Rohit, Bonini, Nicola, Marzari, Nicola, Reich, Stephanie
Rok vydání:	2011
Předmět:	Condensed Matter - Mesoscale and Nanoscale Physics Condensed Matter - Materials Science
Druh dokumentu:	Working Paper
DOI:	10.1103/PhysRevB.85.115451
Popis:	The dominant phonon wavevectors $q^{*}$ probed by the 2D Raman mode of graphene are highly anisotropic and rotate with the orientation of the polarizer:analyzer direction relative to the lattice. The corresponding electronic transitions connect the electronic equibandgap contours where the product of the ingoing and outgoing optical matrix elements is strongest, showing a finite component along $\bm{K}-\bm{\Gamma}$ that sensitively determines $q^{*}$. We revoke the notion of 'inner' and 'outer' processes. Our findings explain the splitting of the 2D mode of graphene under uniaxial tensile strain. The splitting originates from a strain-induced distortion of the phonon dispersion; changes in the electronic band structure and resonance conditions are negligeable for the 2D Raman spectrum. Comment: 4 pages, 6 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1102.5317 Zobrazit plný text záznamu View this record from Arxiv