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New Findings from Institute of Semiconductor Physics in the Area of Quantum Dots Reported

February 4, 2014

By a News Reporter-Staff News Editor at Physics Week -- Fresh data on Quantum Dots are presented in a new report. According to news reporting out of Novosibirsk, Russia, by VerticalNews editors, research stated, "The magnetoresistance in a two-dimensional array of Ge/Si quantum dots was studied in a wide range of zero magnetic field conductances, where the transport regime changes from a hopping to a diffusive one. The behavior of the magnetoresistance is found to be similar for all samples--it is negative in weak fields and becomes positive with increasing magnetic field."

Our news journalists obtained a quote from the research from the Institute of Semiconductor Physics, "The result apparently contradicts existing theories. To explain experimental data we suggest that clusters of overlapping quantum dots are formed. These clusters are assumed to have metal-like conductance, the charge transfer taking place via hopping between the clusters. Relatively strong magnetic field shrinks electron wavefunctions, decreasing inter-cluster hopping and, therefore, leading to a positive magnetoresistance. Weak magnetic field acts on 'metallic' clusters, destroying the interference of the electron wavefunctions corresponding to different paths (weak localization) inside clusters. The interference may be restricted either by inelastic processes, or by the cluster size."

According to the news editors, the research concluded: "Taking into account weak localization inside clusters and hopping between them within the effective medium approximation, we extract effective parameters characterizing charge (magneto-) transport."

For more information on this research see: Universal behavior of magnetoresistance in quantum dot arrays with different degrees of disorder. Journal of Physics Condensed Matter, 2013;25(50):505801.

Our news journalists report that additional information may be obtained by contacting N.P. Stepina, Institute of Semiconductor Physics, 630090 Novosibirsk, Russia. Additional authors for this research include E.S. Koptev, A.G. Pogosov, A.V. Dvurechenskii, A.I. Nikiforov, E.Y. Zhdanov and Y.M Galperin.

Keywords for this news article include: Russia, Eurasia, Novosibirsk, Quantum Dots, Nanotechnology, Quantum Physics, Magnetoresistance, Emerging Technologies.

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Source: Physics Week

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