电荷中性点石墨烯霍尔棒中的涨落诱导磁电阻
Fluctuation-induced magnetoresistance in graphene Hall bars at charge neutrality
浏览论文内容
中文总结 AI 辅助
本文发展电荷中性点石墨烯霍尔棒中热涨落诱导正磁电阻的定量理论，给出解析表达式，并揭示其依赖于霍尔棒几何与取向及动量弛豫。
中文摘要 AI 辅助
在温度区间 $T\sim 50 - 100 K$ 内，石墨烯器件中电子-电子碰撞的速率可能超过由无序和电子-声子散射引起的动量弛豫速率。在该区间内，电子液体的运动可由流体动力学方程描述。在流体动力学近似下，在电荷中性点，电流与流体动力学流动解耦，系统的电导率等于电子液体的本征电导率 $\sigma_0$。最近研究表明，由热涨落引起的电荷输运与流体动力学流动之间的耦合增强了系统的宏观电导率，并在相对较弱的磁场下导致非常强的正磁电阻（MR）。在此，我们发展了电荷中性点处 MR 涨落机制的定量理论，并获得了石墨烯霍尔棒中 MR 的解析表达式。MR 对磁场 $H$ 的函数依赖关系对霍尔棒的几何形状及其相对于电流的取向敏感。我们还考虑了动量弛豫对 MR 的影响。
英文摘要
In the temperature interval $T\sim 50 - 100 K$, the rate of electron-electron collisions in graphene devices may exceed the momentum relaxation rate due to disorder and electron-phonon scattering. In this regime, the motion of the electron liquid may be described by the hydrodynamic equations. In the hydrodynamic approximation, at the charge neutrality point the electric current is decoupled from the hydrodynamic flow, and the conductivity of the system is equal to the intrinsic conductivity of the electron liquid, $σ_0$. It was recently shown that the coupling of charge transport and hydrodynamic flow induced by the thermal fluctuations enhances the macroscopic conductivity of the system and results in very strong positive magnetoresistance (MR) at relatively weak fields. Here we develop a quantitative theory of the fluctuation mechanism of MR at charge neutrality and obtain analytic expressions for MR in graphene Hall bars. The functional dependence of MR on the magnetic field $H$ is sensitive to the Hall bar geometry and orientation relative to the current. We also account for the effect of momentum relaxation on MR.
发表机构
- University of Washington（华盛顿大学）
- University of Wisconsin-Madison（威斯康星大学麦迪逊分校）
- Northwestern University（西北大学）
机构由 AI 辅助整理，请以论文原文为准。
