FOCUS

Video—Growing a Crystal One Atomic Layer at a Time

Physics 11, 106
An electron microscope captures new atomic layers forming and spreading across the surface of a growing nanocrystal.
J.-C. Harmand et al., Phys. Rev. Lett. (2018)
Inch by inch. Researchers have recorded (see video below) the spread of successive atomic layers across the top surface of this growing nanocrystal.

A crystal grows as each atom falls into its place in an ordered structure, and now a research team has imaged the process with atomic detail for a nanocrystal growing up underneath a liquid droplet. Each new atomic layer of the crystal begins at one corner of the hexagonal top surface, forming an atomic step that spreads across the surface and lifts the droplet by a tiny amount. Explaining the progression of the atomic steps with a simple theory led to insights that could help researchers better understand the crystallization process in other situations.

J.-C. Harmand et al., Phys. Rev. Lett. (2018)
This video shows a gallium arsenide nanocrystal growing beneath a droplet of gold supersaturated with gallium and arsenic. Each successive atomic layer starts at the same corner of the hexagonal top surface and expands in a characteristic way.

In the video, produced by Jean-Christophe Harmand and Gilles Patriarche of the French National Center for Scientific Research (CNRS) and the University of Paris-Saclay and their colleagues, the droplet above the crystal is made of liquid gold that is supersaturated with gallium and arsenic. The saturation causes the two elements to drop out of solution and form a gallium arsenide nanocrystal, which the team continuously images using a transmission electron microscope. As seen from above, the front edge of the expanding step changes from convex to concave as it moves across the surface. The researchers developed a theory that explains this shape evolution, showing the influence of the energy of the advancing step and of the boundaries on the process of crystal growth.

This research is published in Physical Review Letters.

–David Ehrenstein

David Ehrenstein is a Senior Editor for Physics.


Subject Areas

Condensed Matter Physics

Related Articles

Vortex Jets Spotted in Superconductors
Materials Science

Vortex Jets Spotted in Superconductors

Researchers have identified and studied vortex jets—streams of swirling electrons—that can form at edge defects in current-carrying superconductors. Read More »

A Supersolid Disk
Condensed Matter Physics

A Supersolid Disk

Researchers have created a disk-shaped supersolid, an achievement that could provide new routes to exploring previously unseen states of matter. Read More »

The Two Structures of Hot Dense Ice
Condensed Matter Physics

The Two Structures of Hot Dense Ice

Experiments indicate that superionic ice can exist in two stable crystal structures. Read More »

More Articles