Hyperspectral electromechanical imaging at the nanoscale: Dynamical backaction, dissipation and quantum fluctuations

TL;DR

This paper introduces a novel nanoscale imaging platform that combines heat application and fluctuation measurement to study nanomechanical dynamics, revealing quantum fluctuation effects and dissipation in a defected nanowire.

Contribution

The work presents a new scanning nanomechanical noise microscopy platform capable of imaging and analyzing nanoscale thermal and mechanical fluctuations with high resolution.

Findings

The platform can image thermally activated nanomechanical dynamics.

A thermal backaction model links structure, dissipation, and fluctuations.

Quantum fluctuations dominate the vibrational state under e-beam excitation.

Abstract

We report a new scanning nanomechanical noise microscopy platform enabling to both heat and acquire the fluctuations of mechanical nanostructures with nanometric resolution. We use this platform to image the thermally activated nanomechanical dynamics of a model system consisting of a $40\,\mathrm{nm}$ diameter single-defect nanowire, while scanning a localized heat source across its surface. We develop a thermal backaction model, which we use to demonstrate a close connection between the structure of the nanowire, its thermal response, its dissipation and its fluctuations. We notably show that the defect behaves as a single fluctuation hub, whose e-beam excitation yields a far off-equilibrium vibrational state, largely dominated by the quantum fluctuations of the heating source. Our platform is of interest for future quantitative investigation of fundamental nanoscale dynamical phenomena, and appears as a new playground for investigating quantum thermodynamics in the strongly dissipative regime and at room temperature.