Macroscopic quantum tunneling in nanoelectromechanical systems

TL;DR

This paper explores the possibility of observing macroscopic quantum tunneling in nanoelectromechanical systems, specifically graphene and carbon nanotubes, highlighting the conditions and challenges for experimental realization.

Contribution

It proposes a method to access quantum phenomena in strongly deflected nanomechanical systems via nonlinear electromechanical potential near metastable points.

Findings

MQT crossover temperatures in the milli-Kelvin range

Carbon nanotubes are promising candidates for observing MQT

Experimental demonstration is challenging but feasible

Abstract

The experimental observation of quantum phenomena in mechanical degrees of freedom is difficult, as the systems become linear towards low energies and the quantum limit, and thus reside in the correspondence limit. Here we investigate how to access quantum phenomena in flexural nanomechanical systems which are strongly deflected by a voltage. Near a metastable point, one can achieve a significant nonlinearity in the electromechanical potential at the scale of zero point energy. The system could then escape from the metastable state via macroscopic quantum tunneling (MQT). We consider two model systems suspended atop a voltage gate, namely, a graphene sheet, and a carbon nanotube. We find that the experimental demonstration of the phenomenon is currently possible but demanding, since the MQT crossover temperatures fall in the milli-Kelvin range. A carbon nanotube is suggested as the most promising system.