Selective nonresonant excitation of vibrational modes in suspended graphene via vibron-plasmon interaction

TL;DR

This paper presents a theoretical study of how an ac-electrical field can selectively excite vibrational modes in suspended graphene through vibron-plasmon interactions, revealing a geometrical resonance that enhances mode-specific pumping.

Contribution

It introduces a novel mechanism for selective vibrational mode excitation in graphene via plasmonic coupling, demonstrating geometrical resonance effects in a suspended graphene system.

Findings

Efficient mode-specific pumping occurs when mechanical and plasma wave numbers match.

Geometrical resonance significantly enhances vibrational excitation.

The pumping intensity increases with the wave number of the mechanical mode.

Abstract

We theoretically study a doped graphene ribbon suspended over a trench and subject to an ac-electrical field polarized perpendicularly to the graphene plane. In such a system, the external ac-field is coupled to the relatively slow mechanical vibrations via plasmonic oscillations in the isolated graphene sheet. We show that the electrical field generates an effective pumping of the mechanical modes. It is demonstrated that in the case of underdamped plasma oscillation, a peculiar kind of geometrical resonance of the mechanical and plasma oscillations appear. Namely the efficiency of pumping significantly increases when the wave number of the mechanical mode is in close agreement with the wave number of the plasma waves. The intensity of the pumping increases with the wave number of the mode. This phenomenon allows selective actuation of different mechanical modes although the driving field is homogeneous.