Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 37: Transport: Quantum dots, wires, point contacts 3 (TT, jointly with HL)

HL 37.8: Vortrag

Dienstag, 12. März 2013, 11:45–12:00, H20

Helical nuclear spin order and conduction reduction in two subband quantum wires — •Tobias Meng and Daniel Loss — Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland

In quantum wires, the hyperfine coupling between conduction electrons and nuclear spins can lead to an ordering of the latter at low temperatures. This order acts back onto the electrons and gaps out part of their spectrum. In the presence of two subbands with distinct Fermi momenta k_F1 and k_F2, we discuss how the nuclear spins order in a superposition of two helices with pitches π/k_F1 and π/k_F2, thus exhibiting a beating patter. This ordering results in a reduction of the electronic conductance in two steps of e²/h upon lowering the temperature.