Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 7: Symposium: Atomic Wires at Surfaces I
(Invited Speakers: Franz Himpsel, Hanno Weitering, Han Woong Yeom)

O 7.6: Hauptvortrag (ohne Erstattung)

Montag, 25. Februar 2008, 13:00–13:30, HE 101

Phase transitions and fluctuations of metallic atomic wires on silicon — •Han Woong Yeom — CAWL, Yonsei University, Seoul, Korea

Wire-type metals in nano scale are essential for nano/molecular electronics and their fundamental properties are challenging with various exotic ground states and fluctuations. As an unconventional form of such 1D metallic systems, we have investigated the self-organized metallic atomic wires on flat and vicinal Si surfaces such as In/Si(111) [1, 2, 3], Au/Si(111) [4], Au/Si(557) [5], and Au/Si(553) [6], and Pb/Si(557) [7]. For some of these systems, we observed Peierls-type phase transitions due to the 1D bands nested fully with electron fillings of 1/2 or 1/3 [1-3, 5, 6]. In the present talk, I will review the achievements so far and the present debates [8] on these phase transitions. A few issues related to the transitions will be introduced such as (i) the impurity control over the Tc, the band gap [4], and the solitonic dynamic fluctuation [9], and (ii) the atomic-scale characterization of the embryonic charge-density wave order [10]. I also raise the question of why some of these systems like Au/Si(111) and Pb/Si(557) are robust against Peierls instability down to fairly low temperature [7]. [1] H. W. Yeom et al., PRL 82, 4898 (1999); [2] J. R. Ahn et al., PRL 93, 106401 (2004); [3] S. J. Park et al., PRL 93, 106402 (2004); [4] W. H. Choi et al., PRL, submitted; [5] J. R. Ahn et al., PRL 91, 196403 (2003); [6] J. R. Ahn et al., PRL 95, 196402 (2005); [7] K. S. Kim et al., PRL, in press; [8] H. W. Yeom, PRL 97, 189701 (2006); [9] S. J. Park et al., PRL 95, 126102 (2005); [10] P. G. Kang et al., PRL, submitted.