Shanks Daniel N, Mahdikhanysarvejahany Fateme, Stanfill Trevor G, Koehler Michael R, Mandrus David G, Taniguchi Takashi, Watanabe Kenji, LeRoy Brian J, Schaibley John R
Department of Physics, University of Arizona, Tucson, Arizona 85721, United States.
IAMM Diffraction Facility, Institute for Advanced Materials and Manufacturing, University of Tennessee, Knoxville, Tennessee 37920, United States.
Nano Lett. 2022 Aug 24;22(16):6599-6605. doi: 10.1021/acs.nanolett.2c01905. Epub 2022 Aug 15.
Controlling the flow of charge neutral interlayer exciton (IX) quasiparticles can potentially lead to low loss excitonic circuits. Here, we report unidirectional transport of IXs along nanoscale electrostatically defined channels in an MoSe-WSe heterostructure. These results are enabled by a lithographically defined triangular etch in a graphene gate to create a potential energy "slide". By performing spatially and temporally resolved photoluminescence measurements, we measure smoothly varying IX energy along the structure and high speed exciton flow with a drift velocity up to 2 × 10 cm/s, an order of magnitude larger than previous experiments. Furthermore, exciton flow can be controlled by saturating exciton population in the channel using a second laser pulse, demonstrating an optically gated excitonic transistor. Our work paves the way toward low loss excitonic circuits, the study of bosonic transport in one-dimensional channels, and custom potential energy landscapes for excitons in van der Waals heterostructures.
控制电荷中性层间激子（IX）准粒子的流动可能会带来低损耗的激子电路。在此，我们报道了在MoSe-WSe异质结构中，IX沿着纳米级静电定义通道的单向传输。这些结果是通过在石墨烯栅极中进行光刻定义的三角形蚀刻来创建势能“滑梯”实现的。通过进行空间和时间分辨的光致发光测量，我们测量了沿结构平滑变化的IX能量以及高达2×10 cm/s的漂移速度的高速激子流，这比之前的实验大一个数量级。此外，通过使用第二个激光脉冲使通道中的激子数量饱和，可以控制激子流，展示了一种光控激子晶体管。我们的工作为低损耗激子电路、一维通道中玻色子传输的研究以及范德华异质结构中激子的定制势能景观铺平了道路。
