Negative Magnetoresistance in Viscous Flow of Two-Dimensional Electrons
Negative Magnetoresistance in Viscous Flow of Two-Dimensional Electrons
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DOI：
10.1103/physrevlett.117.166601
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发表时间：
2016-10-11
影响因子：
8.6
通讯作者：
Alekseev, P. S.
中科院分区：
文献类型：
--
作者：
Alekseev, P. S.
在低温下，在非常干净的二维(2D)样品中，电子与静态缺陷和声子碰撞的平均自由程变得大于样品宽度。在这种情况下，电子的传输是通过形成电子流体的粘性流动来进行的。我们研究了2D电子在垂直于2D层的磁场中的粘性流动。我们计算了粘滞系数作为磁场和温度的函数。非对角线粘性系数决定了二维水动力波的频散。磁场中对角线粘度的减小导致了负磁电阻效应，这种效应与温度和尺寸有关。我们的分析表明，这种粘性机制是最近在超高迁移率的GaAs量子阱中观察到的巨负磁阻的原因。我们的结论是，在中等磁场下，这些结构中的2D电子应被视为粘性流体。
At low temperatures, in very clean two-dimensional (2D) samples, the electron mean free path for collisions with static defects and phonons becomes greater than the sample width. Under this condition, the electron transport occurs by formation of a viscous flow of an electron fluid. We study the viscous flow of 2D electrons in a magnetic field perpendicular to the 2D layer. We calculate the viscosity coefficients as the functions of magnetic field and temperature. The off-diagonal viscosity coefficient determines the dispersion of the 2D hydrodynamic waves. The decrease of the diagonal viscosity in magnetic field leads to negative magnetoresistance which is temperature and size dependent. Our analysis demonstrates that this viscous mechanism is responsible for the giant negative magnetoresistance recently observed in the ultrahigh-mobility GaAs quantum wells. We conclude that 2D electrons in those structures in moderate magnetic fields should be treated as a viscous fluid.