Tunable dynamics of a flake on graphene: Libration frequency

Abstract

In this paper we investigated the interaction between a graphene nanoflake anchored to the 2D graphene monolayer. This interaction is attractive but weak and is capable of setting a well defined registry in equilibrium. Rotational and linear displacements from equilibrium registry generate restoring forces, which can be controlled by external agents. Similar flakes can be self-assembled and can also execute simple harmonic motion as if a physical pendulum. Oscillation of a nanoflake about their equilibrium registries resulting in a characteristic libration frequency is predicted. This frequency depends on the size and geometry of the flake. Moreover, the libration frequency, as well as the electronic and magnetic properties of the flake+monolayer systems, can be tuned by a foreign molecule anchored to the flake, by electric charging and applied parallel and perpendicular electric and magnetic fields. When the sliding of the flake is combined with rotation, the friction force can be reduced dramatically. It is surprising that weak interaction can offer such features at nanoscale, which may offer potential applications. Our predictions are obtained by first-principles calculations based on density functional theory.

Sliding friction of graphene/hexagonal –boron nitride heterojunctions: a route to robust superlubricity

“…6c ). Above a load of 0.8 nN/atom the homogeneous system exhibits erratic motion characterized by sudden angular reorientations 32 (see black lines in Fig. 6d ) accompanied by significant displacements in the direction perpendicular to the scan line (not shown).…”

Free-standing and supported phosphorene nanoflakes: Shape- and size-dependent properties

“…Since the interactions of the hydrogen passivated phosphorene nanoflakes with the specific substrates are weak and hence the spacings between them are wide, the libration frequency of these flakes on these substrates is expected to be low as predicted earlier for graphene nanoflakes [70]. Moreover, this libration frequency can be affected by a biological molecule, which can be adsorbed to the flake.…”

“…Nanoflakes can also behave as nanomechanical devices on the surfaces. The nanometer-size flakes of 2D materials on 2D sheets, like graphene flake on graphene [45,46] display crucial dynamical behaviors. It was shown that the translational and rotational displacements of the flakes on graphene surface can generate restoring forces which can lead to a harmonic motion with a characteristic frequency.…”

Mechanical and Electrical Monitoring in the Dynamics of Twisted Phosphorene Nanoflakes on 2D Monolayers

“…On the other side, molecules, atomic clusters even nanoflakes have been widely used to modify electronic properties of 2D materials providing functionalization. − In addition to electronic structure modification, the molecules or nanoflakes can also behave as nanomechanical devices on the surfaces. The design and synthesis of molecular nanomachines have also been reported. , The nanometer-size flakes of 2D materials on 2D sheets, like graphene flake on graphene , display crucial dynamical behaviors. It was shown that the translational and rotational displacements of the flakes on graphene surface can generate restoring forces which can lead to a harmonic motion with a characteristic frequency.…”

“…It was shown that the translational and rotational displacements of the flakes on graphene surface can generate restoring forces which can lead to a harmonic motion with a characteristic frequency. Additionally, this frequency is also dependent on the shape and size of the flake . Recently, the direct imaging of rotating molecules on single-layer graphene sheet was monitored experimentally. , It was observed that the rotation of graphene on h-BN can thermally be induced at a temperature of T > 100 °C .…”