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- Evaldsson, Martin, et al.
(author)
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Spin polarization in modulation-doped GaAs quantum wires
- 2008
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In: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 77:16, s. 165306-1-165306-7
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Journal article (peer-reviewed)abstract
- We study spin polarization in a split-gate quantum wire focusing on the effect of a realistic smooth potential due to remote donors. Electron interaction and spin effects are included within the density functional theory in the local spin density approximation. We find that depending on the electron density, the spin polarization exhibits qualitatively different features. For the case of relatively high electron density, when the Fermi energy EF exceeds a characteristic strength of a long-range impurity potential Vdonors, the density spin polarization inside the wire is practically negligible and the wire conductance is spin-degenerate. When the density is decreased such that EF approaches Vdonors, the electron density and conductance quickly become spin polarized. With further decrease of the density the electrons are trapped inside the lakes (droplets) formed by the impurity potential and the wire conductance approaches the pinch-off regime. We discuss the limitations of the density functional theory in the local spin density approximation in this regime and compare the obtained results with available experimental data.
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- Roso, Violeta, 1970, et al.
(author)
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The dry port concept: connecting container seaports with the hinterland
- 2009
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In: Journal of Transport Geography. - : Elsevier BV. - 0966-6923. ; 17:5, s. 338-345
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Journal article (peer-reviewed)abstract
- The dry port concept is based on a seaport directly connected by rail with inland intermodal terminals where containers can be dealt with in the same way as if they were in a seaport. The main purpose of the article is to extend the theory behind the dry port concept and to define three dry port categories; distant, midrange and close. The findings show that the dry port concept can help identify ways of shifting freight volumes from road to more energy efficient traffic modes that are less harmful to the environment, relieve seaport cities from some congestion and facilitate improved logistics solutions for shippers in the port’s hinterland.
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