Highly Anisotropic Parallel Conduction in the Stepped Substrate of Epitaxial Graphene Grown on Vicinal SiC
Highly Anisotropic Parallel Conduction in the Stepped Substrate of Epitaxial Graphene Grown on Vicinal SiC
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DOI：
10.1007/s10909-015-1277-y
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发表时间：
2015-01
影响因子：
2
通讯作者：
A. Endo;F. Komori;K. Morita;T. Kajiwara;Satoru Tanaka
中科院分区：
文献类型：
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作者：
A. Endo;F. Komori;K. Morita;T. Kajiwara;Satoru Tanaka
我们报道了在邻近的碳化硅(0001)衬底上生长的单层石墨烯外延中量子霍尔效应(QHE)的高度各向异性现象。发展良好的零阻QHE表现为沿台阶的电流，而QHE被明显的正磁阻所掩盖，其电流与跨越台阶的电流具有二次磁场相关性。后者以及霍尔电阻的小斜率表明，由于碳化硅衬底中残留载流子的存在，存在平行导电，尽管似乎与前一个电流方向观察到的零电阻不一致。我们通过假设沿台阶的平行传导是相当大的，但在台阶上实际上是禁止的，来解释各向异性行为。
We report highly anisotropic appearance of the quantum Hall effect (QHE) in epitaxial single-layer graphene grown on a vicinal SiC(0001) substrate. Well-developed QHE with zero resistance manifests itself for the current along the steps, whereas the QHE is obscured by pronounced positive magnetoresistance with quadratic magnetic-field dependence for the current across the steps. The latter, as well as the small slope of the Hall resistance, implies the presence of parallel conduction due to remnant carriers in the SiC substrate, albeit with seeming inconsistency with the zero resistance observed for the former current direction. We interpret the anisotropic behavior by assuming that the parallel conduction is sizable along the steps but is virtually prohibited across the steps.