ABSTRACT
It has been proposed that the Si(557)-Au surface exhibits spin-charge separation in a one-dimensional electron liquid. Two narrowly spaced bands are found which exhibit a well-defined splitting at the Fermi level. That is incompatible with the assignment to a spinon-holon pair in a Luttinger liquid. Instead, we propose that the two bands are associated with two nearly degenerate atomic chains, or a chain of step atoms with two broken bonds. Such an assignment explains why the surface is metallic despite an even number of electrons per unit cell.
ABSTRACT
A strong, gold-induced surface state is found on single-domain Si(111)-(5x2)-Au at low temperatures. Its band dispersion is one dimensional near the Fermi level E(F) and gradually becomes two dimensional towards the bottom of the band, thus providing a model for a continuous transition in dimensionality. A Peierls-like gap is observed in the one-dimensional portion of the band near E(F).
