论文标题
成像石墨烯中欧姆运输的分解
Imaging the breakdown of ohmic transport in graphene
论文作者
论文摘要
欧姆定律描述了当前密度和电场的比例。在固态导体中，欧姆定律由于电子散射过程而出现，这些过程放松了电流。在这里，我们使用氮气胶合中心磁力测定法直接在高迁移率石墨烯单层中制造的狭窄收缩中直接对欧姆定律的局部崩溃进行成像。当电流集中在收缩边缘上，欧姆流动在室温下可见，流量曲线完全由样品几何形状确定。但是，随着温度降低到200 k以下，电流浓度在收缩中心附近。流动模式的变化与从扩散到以不放松电流为主的电子电子散射过程主导的粘性电子传输一致。
Ohm's law describes the proportionality of current density and electric field. In solid-state conductors, Ohm's law emerges due to electron scattering processes that relax the electrical current. Here, we use nitrogen-vacancy center magnetometry to directly image the local breakdown of Ohm's law in a narrow constriction fabricated in a high mobility graphene monolayer. Ohmic flow is visible at room temperature as current concentration on the constriction edges, with flow profiles entirely determined by sample geometry. However, as the temperature is lowered below 200 K, the current concentrates near the constriction center. The change in the flow pattern is consistent with a crossover from diffusive to viscous electron transport dominated by electron-electron scattering processes that do not relax current.
