Regensburg 2004 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 29: Spinabh
ängiger Transport I
HL 29.6: Vortrag
Mittwoch, 10. März 2004, 16:30–16:45, H13
Rashba effect induced localization in quantum networks — •Dario Bercioux1, Michele Governale2, Vittorio Cataudella1, and Vincenzo Marigliano Ramaglia1 — 1Coherentia-INFM and Dipartimento di Fisica Universitá Federico II Napoli Italy — 2NEST-INFM and Scuola Normale Superiore Pisa Italy
Quantum networks are graphs of one-dimensional wires connected at nodes. It has been shown recently that in a particular two-dimensional quantum network, the so called T3, quantum interference due to the Aharon-Bohm effect and to the topology of the network can induce strong localization [1,2]. For two-dimensional networks made up of quantum wires realized in semiconductor heterostructures, spin-orbit coupling due to the structural inversion asymmetry (Rashba effect[3]) may play an important role. We study a quantum network extending in only one-dimension (chain of square loops connected at one vertex) made up of quantum wires with Rashba spin-orbit coupling. This system is a simplified version of a T3, and exhibits the same kind of localization when a magnetic field is applied. We show that the Rashba effect may give rise to a localization phenomenon similar to the one induced by magnetic flux. This localization effect can be attributed to the spin precession due to the Rashba effect. Furthermore, we study the effect of disorder on the transport properties of this network .
[1] J. Vidal, R. Mosseri and B. Douçot, Phys. Rev. Lett. 81, 5888 (1998). [2] C. Naud et al., Physica E 12, 190 (2001). [3] Yu A. Bychkov and E.I. Rashba, J. Phys. C: Solid State Phys. 17, 6039 (1984).