J. N. Crain

Atomically accurate Si grating with 5.73 nm period

A vicinal surface of silicon is found that exhibits an atomically accurate step pattern with a period of 5.73 nm, corresponding to 17 atomic rows per (111) terrace. It can be viewed as reconstructed Si(557) surface, where a triple step is combined with a single Si(111)7×7 unit. The driving forces for establishing regular step patterns are discussed.

Atomic scale memory at a silicon surface

The limits of pushing storage density to the atomic scale are explored with a memory that stores a bit by the presence or absence of one silicon atom. These atoms are positioned at lattice sites along self-assembled tracks with a pitch of five atom rows. The memory can be initialized and reformatted by controlled deposition of silicon. The writing process involves the transfer of Si atoms to the tip of a scanning tunnelling microscope. The constraints on speed and reliability are compared with data storage in magnetic hard disks and DNA.

Self-assembly of one-dimensional nanostructures at silicon surfaces

Nanostructures at surfaces and interfaces are a fertile testing ground for bringing the idea of ‘tailored solids’ towards reality. Electronic properties can be controlled systematically by confinement or by interface effects. The presence of a single crystal substrate allows for the self-assembly of highly regular nanoobjects, such as stripes and strings of dots with sizes of about 10 nm. Using silicon as substrate facilitates the electronic integration of nanodevices into micro-electronics. We speculate how such structures might evolve into future devices, such as data storage arrays with densities of Terabits/cm 2 and self-assembled,

One-dimensional electronic states at surfaces

One-dimensional electron systems can now be synthesized at stepped surfaces by self-assembly of atomic and molecular chains. A wide variety of adsorbate and substrate combinations provides opportunities for systematically tailoring electronic properties, such as the intra-chain and inter-chain coupling, the electron count, magnetic moment and the Coulomb interaction. Angle-resolved photoemission with synchrotron radiation is an ideal probe to reveal the complete set of quantum numbers for electrons at an ordered surface, i.e. energy, momentum parallel to the surface, spin and point group symmetry. Interesting electronic features are discussed, such as spin-charge separation in a Luttinger liquid, charge density waves, the Peierls gap, mixed dimensionality and one-dimensional quantum well states.

Fermi surfaces of surface states on Si(111)-Ag, Au

Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on

Thermal decomposition of surfactant coatings on Co and Ni nanocrystals

\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Ag},

One-dimensional Gd-induced chain structures on Si(111) surfaces

\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Au},

Functionalization of silicon step arrays I: Au passivation of stepped Si(111) templates

and

Functionalization of silicon step arrays II: Molecular orientation of alkanes and DNA

\mathrm{Si}(111)\sqrt{21}\ifmmode\times\else\texttimes\fi{}\sqrt{21}\ensuremath{-}(\mathrm{Ag}+\mathrm{Au}).