title: Spin-orbit engineering in transition metal dichalcogenide alloy monolayers.
abstract: Binary transition metal dichalcogenide monolayers share common properties such as a direct optical bandgap, spin-orbit splittings of hundreds of meV, light-matter interaction dominated by robust excitons and coupled spin-valley states. Here we demonstrate spin-orbit-engineering in Mo(1-x)WxSe2 alloy monolayers for optoelectronics and applications based on spin- and valley-control. We probe the impact of the tuning of the conduction band spin-orbit spin-splitting on the bright versus dark exciton population. For MoSe2 monolayers, the photoluminescence intensity decreases as a function of temperature by an order of magnitude (4-300 K), whereas for WSe2 we measure surprisingly an order of magnitude increase. The ternary material shows a trend between these two extreme behaviours. We also show a non-linear increase of the valley polarization as a function of tungsten concentration, where 40% tungsten incorporation is sufficient to achieve valley polarization as high as in binary WSe2.
authors.affiliation: Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France.
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.affiliation: Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France.
authors.forename: Cedric
authors.initials: C
authors.lastname: Robert
authors.affiliation: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Aslihan
authors.initials: A
authors.lastname: Suslu
authors.affiliation: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Chen
authors.affiliation: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Sijie
authors.initials: S
authors.lastname: Yang
authors.affiliation: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Alamdari
authors.affiliation: Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France.
authors.forename: Iann C
authors.initials: IC
authors.lastname: Gerber
authors.affiliation: Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Amand
authors.affiliation: Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Marie
authors.affiliation: School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Sefaattin
authors.initials: S
authors.lastname: Tongay
authors.affiliation: Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077 Toulouse, France.
authors.forename: Bernhard
authors.identifier: http://orcid.org/0000-0003-0226-7983
authors.initials: B
authors.lastname: Urbaszek