By applying a current, atoms could even be made to hop from the surface to the tip and back again. It became apparent that as the STM tip moved, mechanical forces could slide atoms along the surface. ‘And after we did some careful experimentation, we realised that some of the changes were not spontaneous – we were actually inducing these movements of atoms.’ ‘As we went along, we noticed that there were changes on the surface as we were scanning it over and over,’ he remembers. ’Īvouris and his team would work late into the night to minimise the effect that vibrations made by people walking around the building would have on their ultra-precise experiments. ‘It was so different to what diffraction had told us at sort of a macroscopic average structure, there were so many local variations, defects, different domains of structures. ‘When the STM came along, I got involved early on and started seeing what we usually refer to as “the atoms” – basically some representation of the charge density of the atomic arrangements.
Prior to these discoveries, Avouris was using diffraction methods to study the chemistry and physics of solid surfaces, but he quickly realised the power of the new techniques.
We got excited that besides being able to see ‘the atoms’, we could also make changes in that scale Today, many instruments incorporate the two systems into the same device, allowing force and current to be analysed simultaneously. Four years later, Binnig patented the atomic force microscope (AFM), a similar device that probes materials’ atomic structures by measuring the force between sample and tip, rather than electric current as is the case with the STM. In 1981, IBM’s Gerd Binnig and Heinrich Rohrer designed the first scanning tunnelling microscope (STM), an invention that soon saw them awarded a physics Nobel prize.
The first holy grail paper was written by IBM researcher Phaedon Avouris, excited by the power of new tools that were enabling chemists to manipulate matter at the atomic level.
0 kommentar(er)
