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Updated: May 2, 2026

Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
Possible evidence for helical nuclear spin order in GaAs quantum wires
C P Scheller1, T-M Liu1, G Barak2
1Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
Abstract:
We present transport measurements of cleaved edge overgrowth GaAs quantum wires. The conductance of the first mode reaches 2e(2)/h at high temperatures T≳10 K, as expected. As T is lowered, the conductance is gradually reduced to 1e(2)/h, becoming T independent at T≲0.1 K, while the device cools far below 0.1 K. This behavior is seen in several wires, is independent of density, and not altered by moderate magnetic fields B. The conductance reduction by a factor of 2 suggests lifting of the electron spin degeneracy in the absence of B. Our results are consistent with theoretical predictions for helical nuclear magnetism in the Luttinger liquid regime.
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