Ab initio study of Tl on Si(111)-(3×1) surface

Abstract

The surface reconstruction, (3×1), induced by Tl adsorption on a Si(111) surface has been studied using first‐principles density‐functional calculations within the generalized gradient approximation. Three different possible adsorption sites have been considered: 1/3 monolayer (ML) of Tl on the Si(111)‐(3×1) surface with (i) a T4 site (directly above a second‐layer Si atom), (ii) an H3 site (this site is directly above a fourth‐layer Si atom), and 2/3 ML of Tl adsorption on this surface in (iii) a T4–H3 site (one Tl atom on a T4 site and the following one on an H3 site). It is calculated that the T4–H3 site is more favorable than the other two. The stability of the Tl/Si(111)‐(3×1) surface can be related to the amount of the Tl coverage and Si=Si double bond. We also present the electronic band structures for the T4–H3 site as well as the corresponding charge‐density plots.

Superconductivity in thallium double atomic layer and transition into an insulating phase intermediated by a quantum metal state

“…Superconductivity in thallium double atomic layer and transition into an insulating phase intermediated by a quantum metal state S Ichinokura 1 , L V Bondarenko 2,3 , A Y Tupchaya 2,3 , D V Gruznev 2,3 , A V Zotov 2,3,4 , A A Saranin 2,3 and S Hasegawa 1 [29,30] like other Group III metals, but it induces also the × 3 1 reconstruction [29,31] akin to that typical for alkali metals. In addition, one monolayer of Tl forms a specific × 1 1 reconstruction [23,29,32,33] having a structure of a pseudomorphic layer where Tl atoms occupy every T 4 sites atop a bulk-truncated Si(1 1 1) surface [34][35][36].…”

“…In particular, deposition of Tl submonolayers onto the Si(1 1 1) × 7 7 template results in formation of the ordered arrays of magic clusters [22][23][24][25][26][27][28]. Due to a variable valency, one or three, Tl induces the × 3 3 reconstruction 2 S Ichinokura et al [29,30] like other Group III metals, but it induces also the × 3 1 reconstruction [29,31] akin to that typical for alkali metals. In addition, one monolayer of Tl forms a specific × 1 1 reconstruction [23,29,32,33] having a structure of a pseudomorphic layer where Tl atoms occupy every T 4 sites atop a bulk-truncated Si(1 1 1) surface [34][35][36].…”