• Tupchaya, A. Y.
• Saranin, A. A.
• Bondarenko, L. V.
• Mihalyuk, A. N.
• Zotov, A. V.
• Wei, C. M.
• Gruznev, D. V.

Abstract

<p>An ordered 4×4-periodicity 2D compound has been found in the (Tl, Pb)/Si(111) system and its composition, structure and electronic properties have been characterized using low-energy electron diffraction, scanning tunneling microscopy observations and density-functional-theory calculations. The compound has been concluded to contain 9 Tl atoms and 12 Pb atoms per 4×4 unit cell, i.e., 0.56 ML of Tl and 0.75 ML of Pb. Structural model was proposed for the 4×4-(Tl, Pb) compound where building blocks are a hexagonal array of 12 Pb atoms, a triangular array of 6 Tl atoms and a Tl trimer. The proposed structure has a C₃ symmetry and occurs in the two equivalent orientations. The electron band structure of the compound contains two metallic spin-split surface-state bands. Bearing in mind the advanced properties of the known 3×3 2D compound in the same (Tl, Pb)/Si(111) system (i.e., combination of giant Rashba effect and superconductivity), the found 4×4-(Tl, Pb) compound is believed to be a promising object for exploration of its superconductive properties.</p>

Topics

• density
• impedance spectroscopy
• surface
• compound
• theory
• electron diffraction
• band structure
• scanning tunneling microscopy
• superconductivity
• superconductivity