Negative magnetoresistance in ultrananocrystalline diamond:Strong or weak localization?

Electronic transport of ultrananocrystalline diamond involves the interplay between disorder, Anderson localization, and phase coherence. We show that variable range hopping explains many key features of the conductivity including the large low temperature negative magnetoresistance. Our numerical s...

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Bibliographic Details
Published in:Applied physics letters 2008-01, Vol.92 (1), p.012120-012120-3
Main Authors: Choy, T. C., Stoneham, A. M., Ortuño, M., Somoza, A. M.
Format: Article
Language:English
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Summary:Electronic transport of ultrananocrystalline diamond involves the interplay between disorder, Anderson localization, and phase coherence. We show that variable range hopping explains many key features of the conductivity including the large low temperature negative magnetoresistance. Our numerical studies suggest two regimes where the (negative) magnetoresistance varies with magnetic field B such as B 2 or B 1 ∕ 2 , respectively, depending on the ratio of the cyclotron orbital radius and the hopping distance. This agrees with experiment, which also points to the expected T − 1 ∕ 2 temperature dependence of the hopping distance at the critical field.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.2826542