Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 50: Poster: Nanostructures on Surfaces II
O 50.2: Poster
Dienstag, 13. März 2018, 18:15–20:30, Poster B
Density functional theory investigation of rare earth silicide nanowires — •Kris Holtgrewe1, Wolf Gero Schmidt2, and Simone Sanna1 — 1Institut für Theoretische Physik, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Gießen — 2Department Physik, Universität Paderborn, Warburger Str. 100, D-33098 Paderborn
Quasi one-dimensional electron systems are of fundamental interest both because of their unusual physical properties and for devices on nanometer scale. A prototype for these systems are rare earth (RE) silicide nanowires on silicon(001) surfaces. They grow self-organized controlled by macroscopic parameters such as temperature and amount of deposited RE.
Unfortunately, the knowledge about nanowires' detailed atomic structure, which is crucial for understanding their physical properties, is still incomplete. We have investigated different wire models from first-principles within density functional theory (DFT). Thereby erbium is chosen as a prototypical trivalent rare earth ion, its 4f-electrons treated as frozen states in the atomic core.
We categorized the models corresponding to six degrees of freedom: width, height, depth of burial, unit cell orientation, roof reconstruction and the underlying bulk RE silicide structure (hexagonal/tetragonal). After comparing the formation energy within ab-initio thermodynamics, electronic band structures and densities of states are calculated for the stable wires. Structural and electronic properties are discussed and compared with available STM, STS and ARPES measurements.