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HL: Fachverband Halbleiterphysik

HL 60: Graphene: Raman Spectroscopy

HL 60.1: Vortrag

Mittwoch, 28. März 2012, 15:30–15:45, ER 164

Substrate dependence of the Raman 2D line of graphene — Alejandro Molina-Sanchez¹ and •Ludger Wirtz^1,2 — ¹Institute for Electronics, Microelectronics, and Nanotechnology (IEMN), CNRS, Lille, France — ²Laboratory for the Physics of Advanced Materials, University of Luxembourg, Luxembourg

We present ab-initio calculations of phonons of graphene on hexagonal boron-nitride which is an example for an ideal flat insulating substrate. The measured double-resonant Raman spectra display shifts of the G and 2D lines comparing, e.g., the spectrum of graphene on silicon dioxide with the spectra of suspended graphene [1] and of graphene on hexagonal boron nitride [2]. In this work, we investigate the influence of the dielectric screening by the substrate on the electron-phonon coupling between the highest-optical phonon branch and the pi-bands of graphene [3]. This enables us to give an explanation for the substrate dependence of the Raman 2D peak position.

References:
S. Berciaud, S. Ryu, L.E. Brus, T.F. Heinz, arXiv:0901.0729v1 [cond-mat.mtrl-sci]
collaboration with F. Forster, A. Meier, K. Watanabe, T. Taniguchi, and C. Stampfer
M. Lazzeri, C. Attaccalite, L. Wirtz, and F. Mauri, Phys. Rev. B 78, 081406(R) (2008).