Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 41: Electronic structure III
O 41.7: Vortrag
Donnerstag, 30. März 2006, 16:30–16:45, WIL B321
Quantum Size Effects in a decoupled Pb slab on graphitized SiC — •Hugo Dil1, Thorsten Kampen1, Thomas Seyller2, and Karsten Horn1 — 1Department of Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany — 2Instutute of Technical Physics, University of Erlangen-Nürnberg, Erwin-Rommel-Straße 1, 91058 Erlangen, Germany
Quantum size effects (QSE) which occur in metal overlayer when the dimensions become comparable to the de Broglie wavelength, are responsible for a wide variety of novel effects. In almost all previous work on this subject the influence of the substrate is not negligible. The preferred height of Pb layers on Si(111), for example, changes from 8 to 6 monolayers when depositing on either the 7x7 or sqrt3 x sqrt3. This can be either due to the interface atomic or electronic structure.
To study QSE in films decoupled from the substrate, one has to create a quasi free standing metal slab. We have accomplished this by depositing lead at low temperature on a single domain graphite substrate which shows very little interaction with the meal film. This substrate was prepared, according to a recently developed procedure, from H-etched SiC. The measured band structure of the Pb quantum well states shows an almost perfect match to density functional theory calculations for free standing lead slabs. The observed heights corresponds well to those expected from a simple total energy minimization principle.