Regensburg 1998 – wissenschaftliches Programm
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SYD: Symposium Phasenübergänge in Elektronensystemen mit Wechselwirkung
SYD 2: Phasenübergänge in Elektronensystemen mit Wechselwirkung II
SYD 2.6: Fachvortrag
Mittwoch, 25. März 1998, 18:40–19:00, H3
Spin density waves and energy gaps in quantum dots and nanowires — •S.M. Reimann1, M. Koskinen2, and M. Manninen2 — 1Niels Bohr Institute, DK-2100 Copenhagen — 2Department of Physics, Univrsity of Jyvaeskylae, FIN-40351 Jyvaeskylae
We recently found [1]that in the ground state electronic structures of quantum dots (i.e. electrons confined in a harmonic trap) a spin-density wave like state with zero total spin can occur even at rather high densities of the 2DEG. Extending these studies to quasi-1D systems, we found that in quantum wires with a low enough density the ground state has a spin density wave with a wave length pi/kF and is accompanied with a pronounced band gap at the Fermi level. This phase transition to a spin density wave state occurs when the density decreases and/or the one-dimensionality increases. If the nanowires have a finite length, there is a possibility for localized states around the energy gap; this end state is caused by the spin density wave and related to the surface states in nearly free electron metals.
[1] M. Koskinen, M. Manninen and S.M. Reimann, Phys. Rev. Lett. 79, 1389 (1997)