标题： 高质量石墨烯器件中具有菊花链和费米能级钉扎的异常磁阻效应 显示英文标题

标题： Extraordinary magnetoresistance in high-quality graphene devices with daisy chains and Fermi-level pinning

摘要： 我们研究了在室温下基于封装在六方氮化硼(h-BN)中的高质量单层石墨烯的链式异常磁阻(EMR)器件。 我们在器件中实现的最大磁阻(MR)为4.6 x 10^7 %，这是迄今为止EMR器件的最高记录。 磁场灵敏度dR/dB达到104 kohm/T，比封装石墨烯之前的记录高出300%以上，并且与低温(4.2 K)下的最先进的石墨烯霍尔传感器相当。 我们证明，将多个EMR器件链式连接是一种实现任意高灵敏度和信噪比以及极小噪声等效场的新方法，适用于弱磁场检测。 最后，我们展示了样品中金属接触引起的费米能级钉扎现象及其对石墨烯特性、电流分布和EMR性能的影响。 我们强调EMR结构作为基础物理研究中霍尔结构的一种有趣替代方案。 显示英文摘要

摘要： We studied daisy-chained extraordinary magnetoresistance (EMR) devices based on high quality monolayer graphene encapsulated in hexagonal boron nitride (h-BN) at room temperature. The largest magnetoresistance (MR) achieved in our devices is 4.6 x 10^7 %, the record for EMR devices to date. The magnetic field sensitivity, dR/dB, reaches 104 kohm/T, exceeding the previous record set by encapsulated graphene by more than 300 %, and is comparable with state-of-the-art graphene Hall sensors at cryogenic temperatures (4.2 K). We demonstrate that daisy chaining multiple EMR devices is a new way to reach arbitrarily high sensitivity and signal-to-noise ratio, and extremely small noise equivalent field for weak magnetic field detection. Finally, we show the evidence of metal contact-induced Fermi-level pinning in the sample and its influence on graphene properties, current distribution and EMR performance. We highlight the EMR geometry as an interesting alternative to the Hall geometry for fundamental physics studies.