Transport and magnetism in GaMnN nanowires
Final Report Abstract
During this project, lithography techniques where developed to permit detailed magnetic and magnetotransport investigations of individual magnetic nanowires. All wires received from the partner group at Berkeley where characterized, but unfortunately microscopic measurements did not reveal any sign of magnetism. This fact is consistent with our macroscopic magnetic measurements (using conventional SQUID), which show mostly paramagnet and some superparamagnetic contributions to the magnetic behavior of an ensemble of the nanowires, quite likely stemming from precursor materials that are left in the solvent, and not incorporated into the wire. Nevertheless, the lithographic process developed for these investigations have proved to be very useful tools for investigations in other systems. That are currently being employed in investigations of many other systems, ranging from Graphen nanodevices to magnetic based high frequency component. During the course of the project, the methods where applied to magnetotransport investigations of microscopic Hall bars based on HgTe, where they uncovered unusual weak localization behavior in materials with a Dirac band-structure.
Publications
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Single valley Dirac fermions in zero-gap HgTe quantum wells. Nature Physics (June 2010)
B. Büttner, C.X. Liu, G. Tkachov, E.G. Novik, C. Brüne, H. Buhmann, E.M. Hankiewicz, P. Recher, B. Trauzettel, S.C. Zhang and L.W. Molenkamp
