Generation of Large Vortex-Free Superfluid Helium Nanodroplets

TL;DR

This paper reports the successful generation of large, vortex-free superfluid helium nanodroplets up to 10^8 atoms, enabling new possibilities for studying metastable nanostructures in a vortex-free environment.

Contribution

It demonstrates a method to produce large vortex-free helium nanodroplets and identifies their size limits, advancing the understanding of superfluid nanostructure formation.

Findings

Vortex-free helium nanodroplets can be generated up to 10^8 atoms.

Single compact structures dominate in droplets up to 10^8 atoms.

Vortex-free droplets provide a platform for studying metastable nanostructures.

Abstract

Superfluid helium nanodroplets are an ideal environment for the formation of metastable, self-organized dopant nanostructures. However, the presence of vortices often hinders their formation. Here, we demonstrate the generation of vortex-free helium nanodroplets and explore the size range in which they can be produced. From x-ray diffraction images of xenon-doped droplets, we identify that single compact structures, assigned to vortex-free aggregation, prevail up to $10^8$ atoms per droplet. This finding builds the basis for exploring the assembly of far-from-equilibrium nanostructures at low temperatures.