论文标题
山谷传导带电子的寿命单层中WSE $ _2 $
Valley lifetimes of conduction band electrons in monolayer WSe$_2$
论文作者
论文摘要
研究二维过渡金属二分法源的主要任务之一是山谷寿命的确定。在这项工作中，我们将时间分辨的Kerr旋转与电气传输测量相结合，以探索单层WSE $ _2 $的自由传导带电子的栅极依赖性山谷寿命。在将费米能调整为传导带时，我们观察到各个山谷寿命的强烈减少，这与自旋轨道和电子音出散射都一致。我们通过将光学激发谷极化的明亮Trions散射到黑暗状态下通过间隔散射来解释山谷极化的形成。此外，我们表明必须修改常规的时间分辨的Kerr旋转测量方案以说明光诱导的栅极筛选效果。忽略这种适应可能会导致从与门相关的光学测量结果得出的错误结论，并且可以完全掩盖真正的栅极依赖性山谷动力学。
One of the main tasks in the investigation of 2-dimensional transition metal dichalcogenides is the determination of valley lifetimes. In this work, we combine time-resolved Kerr rotation with electrical transport measurements to explore the gate-dependent valley lifetimes of free conduction band electrons of monolayer WSe$_2$. When tuning the Fermi energy into the conduction band we observe a strong decrease of the respective valley lifetimes which is consistent with both spin-orbit and electron-phonon scattering. We explain the formation of a valley polarization by the scattering of optically excited valley polarized bright trions into dark states by intervalley scattering. Furthermore, we show that the conventional time-resolved Kerr rotation measurement scheme has to be modified to account for photo-induced gate screening effects. Disregarding this adaptation can lead to erroneous conclusions drawn from gate-dependent optical measurements and can completely mask the true gate-dependent valley dynamics.
