@article{665941253dcb42dcbcb61547bc1af0f6,
title = "Valley-polarized exciton dynamics in a 2D semiconductor heterostructure",
abstract = "Heterostructures comprising different monolayer semiconductors provide an attractive setting for fundamental science and device technologies, such as in the emerging field of valleytronics. We realized valley-specific interlayer excitons in monolayer WSe2-MoSe2 vertical heterostructures. We created interlayer exciton spin-valley polarization by means of circularly polarized optical pumping and determined a valley lifetime of 40 nanoseconds. This long-lived polarization enables the visualization of the expansion of a valley-polarized exciton cloud over several micrometers. The spatial pattern of the polarization evolves into a ring with increasing exciton density, a manifestation of valley exciton exchange interactions. Our work introduces van der Waals heterostructures as a promising platform from which to study valley exciton physics.",
author = "Pasqual Rivera and Seyler, {Kyle L.} and Hongyi Yu and Schaibley, {John R.} and Jiaqiang Yan and Mandrus, {David G.} and Wang Yao and Xiaodong Xu",
note = "Funding Information: We thank D. Cobden and F. Wang for helpful discussion. This work is mainly supported by the U.S. Department of Energy (DOE), Basic Energy Sciences (BES), Materials Sciences and Engineering Division (DE-SC0008145 and SC0012509). The spectroscopy work is partially supported by NSF-EFRI-1433496. H.Y. and W.Y. were supported by the Croucher Foundation (Croucher Innovation Award), and the Research Grants Counciland University Grants Committee of Hong Kong (HKU17305914P, HKU9/CRF/13G, AoE/P-04/08). J.Y. and D.G.M. were supported by the DOE, BES, Materials Sciences and Engineering Division. X.X. acknowledges a Cottrell Scholar Award and support from the State of Washington-funded Clean Energy Institute. Device fabrication was performed at the University of Washington Microfabrication Facility and NSF-funded Nanotech User Facility. Data described in this paper are presented in the supplementary materials and are available upon request. X.X. and W.Y. conceived and supervised the project. P.R. and K.L.S. fabricated the samples and performed the experiments, assisted by J.R.S. P.R., K.L.S., and X.X. analyzed data. H.Y. and W.Y. provided theoretical support and performed the simulation. J.Y. and D.G.M. synthesized and characterized the bulk crystal. P.R., K.L.S., X.X., W.Y., and H.Y. cowrote the paper. All authors discussed the results. Publisher Copyright: {\textcopyright} 2016, American Association for the Advancement of Science. All rights reserved.",
year = "2016",
month = feb,
day = "12",
doi = "10.1126/science.aac7820",
language = "English (US)",
volume = "351",
pages = "688--691",
journal = "Science",
issn = "0036-8075",
publisher = "American Association for the Advancement of Science",
number = "6274",
}