Dynamic Local Strain in Graphene Generated by Surface Acoustic Waves.

Fandan, Rajveer; Pedrós, Jorge; Hernández-Mínguez, Alberto; Iikawa, Fernando; Santos, Paulo V; Boscá, Alberto; Calle, Fernando · Nano Lett · 2020

basic_science · Level V

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Abstract

We experimentally demonstrate that the Raman-active optical phonon modes of single-layer graphene can be modulated by the dynamic local strain created by surface acoustic waves (SAWs). In particular, the dynamic strain field of the SAW is shown to induce a Raman scattering intensity variation as large as 15% and a phonon frequency shift of up to 10 cm<sup>-1</sup> for the G band, for instance, for an effective hydrostatic strain of 0.24% generated in single-layer graphene atop a LiNbO<sub>3</sub> piezoelectric substrate with a SAW resonator operating at a frequency of ∼400 MHz. Thus, we demonstrate that SAWs are powerful tools for modulating the optical and vibrational properties of supported graphene by means of the high-frequency localized deformations tailored by the acoustic transducers, which can also be extended to other 2D systems.