METHOD TO CONTROL ‘HOT’ ELECTRONS COMES A STEP CLOSER

LONDON (TIP): In a promising step towards being able to manipulate and control the behaviour of high energy, or ‘hot’, electrons, scientists have, for the first time, identified a method of visualising the quantum behaviour of electrons on a surface.

Hot electrons are necessary for a number of processes and the implications of being able to manipulate their behaviour are far-reaching — from enhancing the efficiency of solar energy, to improving the targetting of radiotherapy for cancer treatment. “Hot electrons are essential for a number of processes — certain technologies are entirely reliant on them. But they’re notoriously difficult to observe due to their short lifespan, about a millionth of a billionth of a second,” said one of the researchers Peter Sloan from University of Bath in England. “This visualisation technique gives us a really new level of understanding,” Sloan noted.

In the experiment, a Scanning Tunnelling Microscope was used to inject electrons into a silicon surface, decorated with toluene molecules. As the injected charge propagated from the tip, it induced the molecules to react and ‘lift off’ from the surface.

By measuring the precise atomic positions from which molecules departed on injection, the team were able to identify that electrons were governed by quantum mechanics close to the tip, and then by more classical behaviour further away.