Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 9: Poster I

HL 9.56: Poster

Monday, March 27, 2006, 15:15–17:45, P3

Quantum coherence and transport in mesoscopic (Ga,Mn)As wires and rings — •Daniel Neumaier, Konrad Wagner, Matthias Reinwald, Werner Wegscheider, and Dieter Weiss — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany

We investigated the coherence length of holes in (Ga,Mn)As mesoscopic wires and rings at mK temperatures. The structures were fabricated using negative elecrton beam lithography and chemical assisted dry etching techniques. Phase coherence is significantly reduced in ferromagnetic conductors, due to magnetism related scattering effects, and coherence phenomena in electronic transport like universal conductance fluctuations (UCF), or the Aharonov-Bohm effect are expected only in samples with very small dimensions. Here we investigate UCFs in (Ga,Mn)As wires with length between 100 and 600 nm and a width of 25 nm as well as in rings with diameters ranging from 100 nm to 200 nm with the same width. We also tried to improve the coherent transport by post-growth low temperature annealing, which significantly reduces the concentration of Mn interstitials. First results will be reported.