Single atom metallic wires of arbitrary length are of immense scientific and technological interest. Much of the novel and exotic physics expected of one-dimensional electronic systems is described in great details by theory, but is still lacking thorough experimental verification and characterization. Electrons confined to one dimension are expected to develop remarkable properties such as Peierls transitions, collective spin and charge modes and Tomonaga Luttinger Liquid behaviour. Understanding 1D electrons also has technological implications owing to the drastic downscaling of devices and interconnects.
Self-assembled Bi nanolines on Si(001)
Self assembled Bi nanolines and a striking Si reconstruction forming on clean Si(001) surfaces when exposed to low doses of bismuth were a promising alternative to step edges and vicinal surface templates. This so-called Haiku stripe offers a number of exceptional features, not least an intriguing 1D electronic state extending along the centre of the Haiku core and the prospect of self assembling a novel category of subsurface atomic chains on Si(001). We were aiming to explore transport in a truly isolated and one-dimensional wire. However, we were not able to connect these nanowires to external leads to do transport measurements.
Self-assembled Mn nanolines on Si(001)
Mn has been found to self-assemble into atomic chains running perpendicular to the surface dimer reconstruction on Si(001). They differ from other atomic chains by a striking asymmetric appearance in filled state scanning tunneling microscopy (STM) images. This has prompted complicated structural models involving up to three Mn atoms per chain unit. Combining STM, atomic force microscopy, and density functional theory we find that a simple necklacelike chain of single Mn atoms reproduces all their prominent features, including their asymmetry not captured by current models. The upshot is a remarkably simpler structure for modeling the electronic and magnetic properties of Mn atom chains on Si(001).