title: Unveiling the pentagonal nature of perfectly aligned single-and double-strand Si nano-ribbons on Ag(110).
abstract: Carbon and silicon pentagonal low-dimensional structures attract a great interest as they may lead to new exotic phenomena such as topologically protected phases or increased spin-orbit effects. However, no pure pentagonal phase has yet been realized for any of them. Here we unveil through extensive density functional theory calculations and scanning tunnelling microscope simulations, confronted to key experimental facts, the hidden pentagonal nature of single- and double-strand chiral Si nano-ribbons perfectly aligned on Ag(110) surfaces whose structure has remained elusive for over a decade. Our study reveals an unprecedented one-dimensional Si atomic arrangement solely comprising almost perfect alternating pentagons residing in the missing row troughs of the reconstructed surface. We additionally characterize the precursor structure of the nano-ribbons, which consists of a Si cluster (nano-dot) occupying a silver di-vacancy in a quasi-hexagonal configuration. The system thus materializes a paradigmatic shift from a silicene-like packing to a pentagonal one.
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Jorge I
authors.initials: JI
authors.lastname: Cerdá
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Jagoda
authors.initials: J
authors.lastname: Sławińska
authors.affiliation: Aix Marseille Université, CNRS, PIIM UMR 7345, 13397 Marseille, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Le Lay
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
authors.forename: Antonela C
authors.initials: AC
authors.lastname: Marele
authors.affiliation: Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.|Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain.|Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Gómez-Rodríguez
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, ICMM-CSIC, Cantoblanco, 28049 Madrid, Spain.
authors.forename: María E
authors.initials: ME
authors.lastname: Dávila