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Controlling the effective mass of quantum well states in Pb/Si(111) by interface engineering


Slomski, B; Meier, F; Osterwalder, J; Dil, J (2011). Controlling the effective mass of quantum well states in Pb/Si(111) by interface engineering. Physical Review. B, Condensed Matter and Materials Physics, 83(3):035409.

Abstract

The in-plane effective mass of quantum well states in thin Pb films on a Bi reconstructed Si(111) surface is studied by angle-resolved photoemission spectroscopy. It is found that this effective mass is a factor of 3 lower than the unusually high values reported for Pb films grown on a Pb reconstructed Si(111) surface. Through a quantitative low-energy electron diffraction analysis the change in effective mass as a function of coverage and for the different interfaces is linked to a change of about 2% in the in-plane lattice constant. To corroborate this correlation, density functional theory calculations are performed on freestanding Pb slabs with different in-plane lattice constants. These calculations show an anomalous dependence of the effective mass on the lattice constant including a change of sign for values close to the lattice constant of Si(111). This unexpected relation is due to a combination of reduced orbital overlap of the 6pz states and altered hybridization between the 6pz and the 6pxy derived quantum well states. Furthermore, it is shown by core-level spectroscopy that the Pb films are structurally and temporally stable at temperatures below 100 K.

© 2011 American Physical Society

Abstract

The in-plane effective mass of quantum well states in thin Pb films on a Bi reconstructed Si(111) surface is studied by angle-resolved photoemission spectroscopy. It is found that this effective mass is a factor of 3 lower than the unusually high values reported for Pb films grown on a Pb reconstructed Si(111) surface. Through a quantitative low-energy electron diffraction analysis the change in effective mass as a function of coverage and for the different interfaces is linked to a change of about 2% in the in-plane lattice constant. To corroborate this correlation, density functional theory calculations are performed on freestanding Pb slabs with different in-plane lattice constants. These calculations show an anomalous dependence of the effective mass on the lattice constant including a change of sign for values close to the lattice constant of Si(111). This unexpected relation is due to a combination of reduced orbital overlap of the 6pz states and altered hybridization between the 6pz and the 6pxy derived quantum well states. Furthermore, it is shown by core-level spectroscopy that the Pb films are structurally and temporally stable at temperatures below 100 K.

© 2011 American Physical Society

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Physics Institute
Dewey Decimal Classification:530 Physics
Language:English
Date:2011
Deposited On:18 Feb 2011 11:59
Last Modified:18 Feb 2018 03:41
Publisher:American Physical Society
ISSN:1098-0121
OA Status:Green
Publisher DOI:https://doi.org/10.1103/PhysRevB.83.035409
Related URLs:http://arxiv.org/abs/1010.5371

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