Materials are defined by their chemical structure – which atoms are placed where. To control their properties, one can either exchange atoms, or change their arrangement. Until recently, there was only one way to manipulate individual atoms on surfaces: scanning probe microscopy. Scanning transmission electron microscopy, on the other hand, has been able to resolve atoms only more recently by focusing the electron beam with sub-atomic precision. This is especially useful in the two-dimensional form of hexagonally bonded carbon called graphene, which has superb electronic and mechanical properties that can be modified by doping the lattice with other elements.
The scattering of the energetic imaging electrons can cause silicon impurities to move through the graphene lattice, revealing a potential for an entirely new kind of atomically precise manipulation of atoms within crystal lattices. The capability for atom-scale engineering of strongly bound materials would open a new vista for nanotechnology, pushing back the boundaries of what has been so far possible with scanning probe techniques and allowing a plethora of materials science questions to be studied at the ultimate level of control.
However, to achieve these goal, improvements in the description of beam-induced displacements, advances in the implantation of heteroatoms into graphene, and a concerted effort towards the automation of manipulations are required. The overall objective of the project was to develop electron-beam manipulation into a practical technique available to the materials science community. The ERC project ATMEN tackled this in a multidisciplinary effort combining innovative computational techniques with pioneering experiments in a uniquely modified advanced scanning transmission electron microscope at the University of Vienna in Austria.
