Bistability and oscillatory motion of natural nano-membranes appearing within monolayer graphene on silicon dioxide

TL;DR

This paper investigates natural nano-membranes in monolayer graphene on SiO2, revealing bistability and oscillatory behavior with potential applications in quantum-electromechanics and mass spectrometry.

Contribution

It demonstrates the existence of ultra-small, intrinsic nano-membranes in graphene and explores their bistability and oscillations under electric fields, a novel observation.

Findings

Nano-membranes with diameters down to 3 nm identified in graphene.

Nano-membranes can switch hysteretically between two states.

Resonance frequency estimated up to 0.4 THz.

Abstract

The recently found material graphene is a truly two-dimensional crystal and exhibits, in addition, an extreme mechanical strength. This in combination with the high electron mobility favours graphene for electromechanical investigations down to the quantum limit. Here, we show that a monolayer of graphene on SiO2 provides natural, ultra-small membranes of diameters down to 3 nm, which are caused by the intrinsic rippling of the material. Some of these nano-membranes can be switched hysteretically between two vertical positions using the electric field of the tip of a scanning tunnelling microscope (STM). They can also be forced to oscillatory motion by a low frequency ac-field. Using the mechanical constants determined previously, we estimate a high resonance frequency up to 0.4 THz. This might be favorable for quantum-electromechanics and is prospective for single atom mass spectrometers.