Abstract

In recent years, it has become possible to create well-ordered semiconductor surfaces with metallic surface states by using self-assembly of metal atoms. Since these states lie in the band gap of the semiconductor, they completely decouple from the substrate. In addition to two-dimensional structures it is possible to obtain arrays of one-dimensional atomic chains, which may be viewed as the ultimate nanowires. The dimensionality can be varied systematically by using vicinal surfaces with variable step spacing. Angle-resolved photoemission and scanning tunnelling spectroscopy reveal surprising features, such as a fractional band filling, nanoscale phase separation into doped and undoped chain segments, and a spin-splitting at a non-magnetic surface. Prospects for one-dimensional electron gas physics in atomic chains are discussed.

Keywords: A. Semiconductors; B. Surfaces and interfaces; C. Scanning tunnelling microscopy; D. Photoelectron spectroscopy

PACS classification codes: 73.20.At; 79.60.-i; 73.21.Hb; 68.65.La

Corresponding author. Tel.: +1 608 263 5590; fax: +1 608 265 2334.
¹ Recipient of the 2007 Davisson–Germer Prize of the APS.