Friday, February 25, 2011
Direct electronic readout of 'artificial atoms': In principle, the spin of electrons in individual atoms can be read-out, but the minuteness of the signals and the difficulty of localising individual atoms limit this technology to highly specialised laboratories. It requires an ultra-high vacuum and costly laser technology. 'It would be considerably more elegant to incorporate atom-like systems into solids,' said Prof. Wieck. In this case, quantum mechanics are helpful: For standard electron densities in semiconductors, the wavelength of electrons (and holes) is several tens of nanometres (nm), which means a distance of 100 atoms. It therefore is not necessary to isolate or insert individual atoms. It suffices to define areas that expand in each direction by about 100 atoms, thus comprising around 1003 = one million atoms.