open access

https://hdl.handle.net/2115/45815

Influence of ordered arrangements of cluster chains on the hopping transport in GaAs : Mn/MnAs hybrids at low temperatures

英語

2011-06-15

American Physical Society

Physical Review B

83(23)

235305

Two different arrangements of cluster chains consisting of elongated MnAs nanoclusters were deposited on (111)B-GaAs substrates by selective-area metal-organic vapor-phase epitaxy. This method allows one a controlled positioning of the nanoclusters on the substrate, offering the possibility to investigate the influence of the nanocluster arrangement on the transport properties of granular hybrid structures. Magnetotransport measurements at low temperatures were performed for both cluster-chain arrangements prepared. In contrast to GaAs: Mn/MnAs hybrids with a random cluster distribution, which usually show a negative magnetoresistance at low temperatures, large positive magnetoresistance effects are observed for cluster-chain arrangements at 15 K. Furthermore, the arrangements exhibit a rectifying behavior of the current-voltage characteristics in the presence of an external magnetic field. The magnitude of both effects correlates with the arrangement of the chains on the substrate and can be explained qualitatively by assuming hopping conduction as the dominant transport mechanism.

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©2011 American Physical Society

1098-0121