Energy band for manipulated atomic structures of Si, GaAs, and Mg on an insulating substrate

Stimulated by recent progress in atom manipulation technology, we study the electronic properties of periodic structures artificially created with atoms on a substrate surface, where constituent atoms are isolated from substrate atoms and interact with one another through neighboring-atom interactions. By reducing the lattice constant d from infinity, the neighboring-atom interaction is gradually turned on, and discrete atomic states broaden to form energy bands. Band structures of a simple one-dimensional (1D) atomic chain, a two-dimensional (2D) square array, and two parallel atomic chains are calculated for various atoms as a function of d using tight-binding theory with universal parameters. All three structures with Si are metallic due to the existence of the {π} bands, inside which the Fermi energy lies. A 1D alternating GaAs atomic chain is also metallic. A 1D Mg chain is insulating with a null band gap at exactly d=4.2 {}, and a 2D Mg square array shows a phase transition: a metallic phase for d5.2 {} and an insulating phase for d{}5.2 {}. {} 1996 The American Physical Society.