近日，瑞士苏黎世联邦理工学院的Christian L. Degen及其研究团队取得一项新进展。经过不懈努力，他们观察到室温下石墨烯中的电流漩涡。相关研究成果 已于2024年4月26日在国际权威学术期刊《科学》上发表。

该研究团队利用纳米级扫描磁强计，在单层石墨烯器件中成像了室温下一种特殊的流体动力输运模式——静止的电流漩涡。随着装置特征尺寸的增大，研究人员观察到电流漩涡逐渐消失，这一发现与流体力学模型的预测相吻合。

研究人员进一步观察到漩涡流动在空穴和电子主导输运状态下都存在，但在双极状态下消失。他们将这种效应归因于接近电荷中性的涡度扩散长度的减小。这项研究工作充分展现了局部成像技术，在揭示奇异介观输运现象方面的强大能力。

据悉，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力学描述的输运特征。

附：英文原文

Title: Observation of current whirlpools in graphene at room temperature

Author: Marius L. Palm, Chaoxin Ding, William S. Huxter, Takashi Taniguchi, Kenji Watanabe, Christian L. Degen

Issue&Volume: 2024-04-26

Abstract: 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.

DOI: 10.1126/science.adj2167

Source: https://www.science.org/doi/10.1126/science.adj2167