Electron–electron interactions in high-mobility conductors can give rise to transport signatures resembling those described by classical hydrodynamics. Using a nanoscale scanning magnetometer, we imaged a distinctive hydrodynamic transport pattern—stationary current vortices—in a monolayer graphene device at room temperature. By measuring devices with increasing characteristic size, we observed the disappearance of the current vortex and thus verified a prediction of the hydrodynamic model. We further observed that vortex flow is present for both hole- and electron-dominated transport regimes but disappears in the ambipolar regime. We attribute this effect to a reduction of the vorticity diffusion length near charge neutrality. Our work showcases the power of local imaging techniques for unveiling exotic mesoscopic transport phenomena.

中文翻译：

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室温下石墨烯中电流漩涡的观察

高迁移率导体中的电子-电子相互作用可以产生类似于经典流体动力学描述的传输特征。使用纳米级扫描磁力计，我们在室温下对单层石墨烯器件中独特的流体动力传输模式（静止电流涡旋）进行了成像。通过测量特征尺寸不断增加的装置，我们观察到当前涡流的消失，从而验证了流体动力学模型的预测。我们进一步观察到，涡流在空穴和电子主导的传输区域中都存在，但在双极区域中消失。我们将这种效应归因于电荷中性附近涡度扩散长度的减小。我们的工作展示了局部成像技术在揭示奇异介观输运现象方面的力量。