Accepted Wednesday Jul 08, 2009
Many quasi one-dimensional (1D) materials are experimental approximations to the textbook models of Peierls instabilities and collective excitations in 1D electronic systems. The recently observed selfassembly of atom wires on solid surfaces has provided fascinating new insights into the nature of their structural and electronic instabilities, both from a real-space and momentum-space perspective. In this Colloquium, we highlight three of the most studied atom wire arrays, all featuring multiple surface state bands. One of these is made of indium atoms on a flat silicon (111) surface, while the two others consist of gold atoms on surfaces that are vicinal to Si(111). In discussing the experimental and theoretical results, we focus on the detailed mechanisms of the observed phase transitions and on the role of microscopic defects.