title: Directional interlayer spin-valley transfer in two-dimensional heterostructures.
abstract: Van der Waals heterostructures formed by two different monolayer semiconductors have emerged as a promising platform for new optoelectronic and spin/valleytronic applications. In addition to its atomically thin nature, a two-dimensional semiconductor heterostructure is distinct from its three-dimensional counterparts due to the unique coupled spin-valley physics of its constituent monolayers. Here, we report the direct observation that an optically generated spin-valley polarization in one monolayer can be transferred between layers of a two-dimensional MoSe2-WSe2heterostructure. Using non-degenerate optical circular dichroism spectroscopy, we show that charge transfer between two monolayers conserves spin-valley polarization and is only weakly dependent on the twist angle between layers. Our work points to a new spin-valley pumping scheme in nanoscale devices, provides a fundamental understanding of spin-valley transfer across the two-dimensional interface, and shows the potential use of two-dimensional semiconductors as a spin-valley generator in two-dimensional spin/valleytronic devices for storing and processing information.
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Schaibley
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Pasqual
authors.identifier: 0000-0002-5909-1686
authors.initials: P
authors.lastname: Rivera
authors.affiliation: Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China.
authors.forename: Hongyi
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Kyle L
authors.initials: KL
authors.lastname: Seyler
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: Jiaqiang
authors.initials: J
authors.lastname: Yan
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.|Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Mandrus
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305- 0044, Japan.
authors.forename: Kenji
authors.identifier: 0000-0003-3701-8119
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Hong Kong, China.
authors.forename: Wang
authors.identifier: 0000-0003-2883-4528
authors.initials: W
authors.lastname: Yao
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.|Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Xiaodong
authors.identifier: 0000-0003-0348-2095
authors.initials: X
authors.lastname: Xu