Low-temperature one-atom-layer 7×7-In phase on Si(111)

• Published in: Surface science Vol. 649; pp. 14 - 19
• Main Authors: Mihalyuk, A.N., Alekseev, A.A., Hsing, C.R., Wei, C.M., Gruznev, D.V., Bondarenko, L.V., Matetskiy, A.V., Tupchaya, A.Y., Zotov, A.V., Saranin, A.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2016
• Subjects: Ab initio random structure searching; Atom–solid interactions; Indium; Low energy electron diffraction; Scanning tunneling microscopy; Silicon; Scanning tunneling microscopy; Silicon; Atom–solid interactions; Ab initio random structure searching; Indium; Low energy electron diffraction
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/j.susc.2016.01.016

The Si(111)-hex-7×3-In reconstruction has been attracted considerable attention due to its superconducting properties occurring in the one-atom-layer metal film. However, the 7×3 periodicity is a characteristic feature of this surface only at room temperature. Upon cooling to low temperatures the 7×3 structure transforms reversibly to the 7×7 one that should not be ignored while considering superconductivity in this system. In the present study, atomic structure of the low-temperature one-atom-layer Si(111)7×7-In phase has been evaluated using scanning tunneling microscopy (STM), low-energy electron diffraction (LEED) and ab initio random structure searching (AIRSS) technique. Basing on the LEED observations, it has been found that the 7×7-In surface incorporates plausibly eight In atoms per 7×7 unit cell (i.e., ~1.14ML In). AIRSS demonstrates occurrence of a set of various surface structures with very close formation energies. Some of their counterparts can be found in the experimental STM images. [Display omitted] •Upon cooling, In/Si(111)-hex-√7×√3 phase transforms reversibly to √7×√7 structure.•The √7×√7 phase contains less In than the hex-√7×√3 surface with 1.2ML In.•The √7×√7 phase incorporates plausibly eight In atoms per √7×√7 unit cell (i.e., ~1.14ML In).•AIRSS reveals occurrence of various surface structures having close formation energies.•Some model structures (albeit not all) have their counterparts in experimental STM images.