科研之友
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摘要
We investigate the magnetotransport properties of epitaxial graphene on SiC(0001), which exhibits a stepped surface with regular terraces and step edges. We observe an anisotropic behavior in the magnetoresistance measured at high magnetic fields for narrow Hall bars patterned on stepped surfaces. If the Hall bar is aligned parallel to the terraces, the conventional quantum Hall effect behavior is observed. In contrast, a predominantly positive magnetoresistance arises if the current crosses many surface steps. The results can be explained by a model which takes into account inter-Landau-level scattering, which is enhanced in the step edge surface region and may enable electron backscattering from one channel to another on the opposite side, resulting in a positive magnetoresistance.
- 出版日期2012-6-1
