Stretchable graphene: a close look at fundamental parameters through biaxial straining.

Ding, Fei; Ji, Hengxing; Chen, Yonghai; Herklotz, Andreas; Dörr, Kathrin; Mei, Yongfeng; Rastelli, Armando; Schmidt, Oliver G · Nano Lett · 2010

basic_science · Level V

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Abstract

Tunable biaxial stresses, both tensile and compressive, are applied to a single layer graphene by utilizing piezoelectric actuators. The Gruneisen parameters for the phonons responsible for the D, G, 2D and 2D' peaks are studied. The results show that the D peak is composed of two peaks, unambiguously revealing that the 2D peak frequency (omega(2D)) is not exactly twice that of the D peak (omega(D)). This finding is confirmed by varying the biaxial strain of the graphene, from which we observe that the shift of omega(2D)/2 and omega(D) are different. The employed technique allows a detailed study of the interplay between the graphene geometrical structures and its electronic properties.