Regensburg 2019 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 95: Semiconductor Substrates: Metallic Nanowires

O 95.6: Vortrag

Freitag, 5. April 2019, 11:45–12:00, H14

Temperature-dependent order-disorder transition in the Si(553)-Au nanowire system — •Bernd Hafke1, Tobias Witte1, Christian Brand1, Simone Sanna2, Christian Braun3, Wolf Gero Schmidt3, and Michael Horn-von Hoegen11Universität Duisburg-Essen, Lotharstr. 1, 47057 Duisburg — 2Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen — 3Universität Paderborn, Pohlweg 55, 33098 Paderborn

Deposition of 0.5 ML Au on Si(553) at 650 C results in the formation of Au double-strand metallic chains with a twofold periodicity along the terraces of the vicinal Si surface. The step edge atoms of the Si terraces are characterized by a threefold periodicity, due to the presence of unoccupied dangling bonds [1,2]. The long-range interaction of the twofold and threefold periodicity is investigated by spot-profile analysis in LEED as function of temperature between 60 K and 190 K. The correlation length of Si step edge atoms along and perpendicular to the steps abruptly decreases upon heating above a temperature of T≈100 K, respectively. These findings are explained within a scenario of an order-disorder transition, where the thermal creation of solitons destroy the long-range ordering. Additionally, time-resolved ultra-fast RHEED experiments show the streak-like intensity, indicative for the twofold periodicity of the Au atoms, to decrease upon intense fs-optical excitation. This indicates transient weakening of the dimerization within the Au double-strand.

[1] S. C. Erwin and F. J. Himpsel, Nature Commun. 1, 58 (2010).

[2] C. Braun, et al. PRB 98, 121402 (2018).

100% | Mobil-Ansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2019 > Regensburg