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Geometric Effects in the Electronic Structure of Atomic Chains

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Date: 02-08-2006
Start Time: 4:00pm
End Time: 5:00pm
Speaker: Jason N. Crain
From: National Institute of Standards and Technology, Gaithersburg, MD
Location: Interschool Lab, 7th floor, Schapiro/CEPSR
Hosted by: Center for Integrated Science

Abstract:

Electron-electron and electron-phonon interactions can lead to unexpected properties in one-dimensional properties that are different than in three-dimensions. In the present study we explore a promising candidate system of "wires" that approach the one-dimensional limit: self-assembled atomic chains on stepped silicon surfaces. Using angle-resolved photoemission and scanning tunneling microscopy we probe the momentum resolved and spatially resolved electronic structures of Si(553)-Au atomic chains. Our findings show geometry plays a key role in the electronic structure demonstrating: (1) the one-dimensional nature of the Fermi surfaces of self-assembled atomic chains [1], (2)the small but measurable two-dimensional coupling that varies with the spacing between chains [2], (3) the formation of quantized resonances in finite chain segments [3], and (4) how electronic effects can influence the length distribution of atomic chains. Such geometrical effects will play a key role in determining the low-temperature properties, such as recently observed charge density wave phases.

[1] J.N. Crain, A. Kirakosian, K.N. Altmann, C. Bromberger, S.C. Erwin, J.L. McChesney, J.L. Lin, and F.J. Himpsel, Phys. Rev. Lett., 90, 176805 (2003).
[2] J.N. Crain, J.L. McChesney, F. Zheng, M.C. Gallagher, P.C. Snijders, M. Bissen, C. Gundelach, S.C. Erwin, and F.J. Himpsel, Phys. Rev. B, 69, 125401 (2004).
[3] J.N. Crain and D.T. Pierce, Science, 307, 703 (2005).