Comment on ‘Bi nanolines on Si(001): registry with substrate’

Abstract

A recent article (Miwa et al 2005 Nanotechnology 16 2427) casts doubt on the four-dimer-wide Haiku model for the Bi nanoline on Si(001), suggesting instead that the three-dimer-wide Miki model (which had been ruled out) is a better fit in particular to x-ray data. The reasons why the Haiku model provides the best fit to all published data among currently proposed structures are discussed, concentrating on the width and registry of the Bi nanoline, and mentioning new data which shows that under appropriate conditions the two structures coexist in the same surface.

1D semiconducting atomic chain of In and Bi on Si(001)

“…We note that there have been recent suggestions that the Bi nanolines have the structure known as the 'Miki' model (where the Bi dimers are in line with the underlying Si substrate dimers, and are separated by a missing surface dimer) [22]. As shown in recent papers [23,24], we believe that this assignment is contradicted by virtually all the evidence available; nevertheless, small islands of 'Miki' structure can remain in the substrate after preparation of a nanoline template [23], so we have modelled the effects of adding In to this structure. We find that it is at least 0.1 eV per pair of In atoms less stable than adding In to the Haiku structure.…”

Reply to Comment on ‘Bi nanolines on Si(001): registry with the substrate’

“…The authors of the previous comment [1] are aware that we have generated some of the most compelling support for the Haiku Si(001)-Bi nanoline geometry [2][3][4][5][6], first proposed by Owen et al [7]. They have, for example, drawn upon our published work for a review article entitled Self-assembled nanowires on semiconductor surfaces that is to be published in the near future [8].…”

“…They have, for example, drawn upon our published work for a review article entitled Self-assembled nanowires on semiconductor surfaces that is to be published in the near future [8]. Briefly, we have (1) performed ab inito theoretical studies of the Haiku nanoline geometry, compared it with other candidate geometries, and found it to have the lowest total energy [2,[4][5][6], (2) performed scanning tunnelling microscopy (STM) studies of the nanoline, and produced: a line profile, a line width estimate and a determination of the Bi-dimer separation for the nanoline geometry on a Si(001) surface, without using H-termination [3,5,6], (3) performed theoretical simulations of the STM constantcurrent topographs and compared these with our experimental images [4][5][6].…”