• Chou, Jyh Pin
• Mihalyuk, Alexey N.
• Tupchaya, Alexandra Y.
• Gruznev, Dimitry V.
• Saranin, Alexander A.
• Wei, Ching Ming
• Zotov, Andrey V.
• Bondarenko, Leonid V.

Abstract

<p>Metastable double-atomic layer of Tl on Si(111) has recently been found to display interesting electric properties, namely superconductivity below 0.96 K and magnetic-field-induced transition into an insulating phase intermediated by a quantum metal state. In the present work, using a set of experimental techniques, including low-energy electron diffraction, scanning tunneling microscopy, angle-resolved photoelectron spectroscopy, in a combination with density-functional-theory calculations, we have characterized atomic and electronic properties of the Tl double layer on Si(111). The double Tl layer has been concluded to contain ∼ 2.4 monolayer of Tl. A top Tl layer has a ‘1 × 1’ basic structure and displays 6 × 6 moiré pattern which originates from various residence sites of Tl atoms. Upon cooling below ∼ 140 K, the 6 × 6 moiré pattern changes to that having a 63×63 periodicity. However, the experimentally determined electron band dispersions show a 1 × 1 periodicity. The calculated band structure unfolded into the 1 × 1 surface Brillouin zone reproduces well the main features of the photoelectron spectra.</p>

Topics

• density
• dispersion
• surface
• phase
• theory
• electron diffraction
• band structure
• scanning tunneling microscopy
• superconductivity
• superconductivity
• angle-resolved photoelectron spectroscopy