atomic manipulations (rus. манипуляция атомами) — intentional movement and positioning of atoms in space.

Description

The ideal process for creating nanostructures is atom-by-atom assembly, as proposed by Richard Feynman in his prophetic article in 1960 [1]. With the development of scanning probe microscopy (SPM), this fantastic prospect became a reality. Among various approaches, SPM has proved to be the simplest and most convenient method of manipulating atoms. An additional advantage of SPM is that it can be used not only as a research tool but also as a tool for influencing atoms at surfaces. It is possible to hook atoms with the tip, move them along the surface to the desired location, remove unnecessary atoms, or deposit additional atoms from the tip using interatomic forces between the end atom of the tip and an atom on the surface, electrostatic forces of the tip acting on the surface, or high density currents. Therefore the same device is used for atomic manipulation and process monitoring, i.e. one can first examine the surface, select an object for manipulation, carry out the manipulation, and then control the result.

The possibility of such atomic manipulation was first demonstrated in 1989 by the group of American physicist D. Eigler (see quantum corral).

Another tool for manipulating atoms is a laser trap (optical tweezers) and its improved version, the magneto-optical trap. Since light is a high-frequency electric and magnetic field, a focused laser beam creates an alternating electric field with a local maximum. When this field interacts with an atom, it changes the distribution of electrons around the atom and induces an electric dipole moment in the atom. Such an atom will be attracted to the area of local maximum of the electric field created by the laser beam. Another force in a laser beam acting on the atoms is light pressure; the atoms absorb photons, acquire the photons' momentum and start scattering. To minimize the scattering the laser frequency should be lower than the frequency at which atoms absorb photons. Laser traps enable almost complete immobilisation of the atoms of vaporised substances that move at a supersonic speed at room temperature, i.e. the traps allow reducing their temperature to near absolute zero. This provides the opportunity for detailed research into the internal structure of atoms, and enables the creation of high-precision atomic clocks. Steven Chu, Claude Cohen-Tannoudji and William D. Phillips were awarded the Nobel Prize in Physics in 1997 for development of methods to cool and trap atoms with laser light. Currently, laser traps and laser tweezers are also widely used in biological research, in particular, to study mechanical properties of biological motors.

Illustrations

Using the interatomic forces between the
Using the interatomic forces between the "last" atom of the tip and an atom on the surface, as well as electrostatic forces applied by the pin to the surface, or using high-density currents, you man engage atoms with the tip, move them on the surface to the desired location, remove unwanted atoms or deposit additional atoms from the tip.

Authors

  • Saranin Alexander A.
  • Shirinsky Vladimir P.

Sources

  1. Feynman R. P. There's plenty of room at the bottom // Eng. and Sci. (Calif. Inst. Technol.). 1960. V. 23, №2. P. 22–29.
  2. Oura K. et al. Surface Science: An Introduction // Springer, 2010 - 452 pp.
  3. Chu S. Laser Trapping of Neutral Particles // Scientific American, 2008. —www.scientificamerican.com/article.cfm?id=steven-chu-laser-trapping-of-neutral&page=7 (reference date: 27.07.2010).

Contact us