Berlin 2005 – scientific programme
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HL: Halbleiterphysik
HL 7: Transporteigenschaften
HL 7.2: Talk
Friday, March 4, 2005, 11:00–11:15, TU P-N226
Electron localization in quantum networks — •Dario Bercioux1,2, Michele Governale3, Vittorio Cataudella1, and Vincenzo Marigliano Ramaglia1 — 1Coherentia-INFN and "Federico II" University of Naples, I-80126, Italy — 2Institut für Theoretische Physik, Universität Regensburg, D-93040, Germany — 3NEST-INFM and Scuola Normale Superiore, Pisa, I-56126, Italy
Quantum networks are graphs of one-dimensional wires connected at nodes. For networks made up of quantum wires realized in semiconductor heterostructures, spin-orbit coupling due to the lack of inversion symmetry in the growth direction (Rashba effect[1]) plays an important role. We show that in particular quantum network extending in only one-dimension (chain of square loops connected at one vertex), Rashba effect gives rise to a electron localization phenomena [2]. This localization effect can be attributed to the spin precession due to the Rashba effect. Similar localization phenomena are observed in presence of magnetic field [3,4]. Both the effects are due to the strong interplay between the external fields and the geometry of the network. Here we present these effect in one- and two-dimensional cases showing that in special situation the interplay of magnetic field and Rashba effect completely destroys the localization effect.
[1] Yu A. Bychkov and E.I. Rashba, J. Phys. C: Solid State Phys. 17, 6039 (1984). [2] D. Bercioux, M. Governale, V. Cataudella and V. Marigliano Ramaglia, Phys. Rev. Lett. 93, 56802 (2004). [3] J. Vidal, R. Mosseri and B. Douçot, Phys. Rev. Lett. 81, 5888 (1998). [4] C. Naud, G. Faini, and D. Mailly, Phys. Rev. Lett. 86, 5104 (2001).