Zhou Zhiwen, Szwed E A, Choksy D J, Fowler-Gerace L H, Butov L V
Department of Physics, University of California San Diego, La Jolla, CA, USA.
Nat Commun. 2024 Nov 1;15(1):9454. doi: 10.1038/s41467-024-53445-5.
In addition to its fundamental interest, the long-distance spin transport is essential for spintronic devices. However, the spin relaxation caused by scattering of the particles carrying the spin limits spin transport. We explored spatially indirect excitons (IXs) in van der Waals heterostructures composed of atomically thin layers of transition-metal dichalcogenides as spin carries. We observed the long-distance spin transport: the spin polarized excitons travel over the entire sample, ~10 micron away from the excitation spot, with no spin density decay. This transport is characterized by the 1/e decay distances reaching ~100 micron. The 1/e decay distances are extracted from fits over the ~10 micron sample size. The emergence of long-distance spin transport is observed at the densities and temperatures where the IX transport decay distances and, in turn, scattering times are strongly enhanced. The suppression of IX scattering suppresses the spin relaxation and enables the long-distance spin transport.
除了其基本的研究价值外，长距离自旋输运对于自旋电子器件至关重要。然而，由携带自旋的粒子散射引起的自旋弛豫限制了自旋输运。我们在由原子级薄的过渡金属二硫属化物层组成的范德华异质结构中探索了空间间接激子（IXs）作为自旋载体。我们观察到了长距离自旋输运：自旋极化激子在整个样品中传播，距离激发点约10微米，且自旋密度没有衰减。这种输运的特征是1/e衰减距离达到约100微米。1/e衰减距离是从对约10微米样品尺寸的拟合中提取的。在IX输运衰减距离以及散射时间大幅增强的密度和温度下，观察到了长距离自旋输运的出现。IX散射的抑制抑制了自旋弛豫并实现了长距离自旋输运。
