Abstact

—We study spin-valley relaxation dynamics in two-dimensional Mo_xW_1–xSe₂/WSe₂ heterobilayers with different relative Mo/W concentration x in the monolayer alloy. Three types of heterobilayers with x = 1.00, 0.50, 0.33 are studied in time-resolved Kerr rotation experiments for different wavelengths and temperatures. The spin-valley relaxation times are found to decrease from ~10 nanoseconds for x = 1.00 to ~50 ps for x = 0.33. The observed relaxation times are limited by the recombination of indirect excitons formed in the heterobilayers. Our results demonstrate that spin-valley relaxation in alloy-based van der Waals heterostructures can be controlled via their chemical composition.

中文翻译：

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Mo x W 1–x Se 2 / WSe 2异质双层中层间激子的自旋谷动力学

摘要

—我们研究了单层合金中具有不同相对Mo / W浓度x的二维Mo _x W _{1– x} Se ₂ / WSe ₂异质双层中的自旋谷弛豫动力学。在时间分辨的Kerr旋转实验中，针对不同的波长和温度，研究了x = 1.00、0.50、0.33的三种类型的异质双层。发现自旋-谷弛豫时间从约10毫微秒减少X = 1.00至〜50皮秒为X= 0.33。观察到的弛豫时间受到异双分子层中形成的间接激子复合的限制。我们的结果表明，合金基范德华异质结构中的自旋谷弛豫可以通过其化学组成来控制。