title: Generation and Evolution of Spin-, Valley-, and Layer-Polarized Excited Carriers in Inversion-Symmetric WSe_{2}.
abstract: We report the spin-selective optical excitation of carriers in inversion-symmetric bulk samples of the transition metal dichalcogenide (TMDC) WSe_{2}. Employing time- and angle-resolved photoelectron spectroscopy (trARPES) and complementary time-dependent density functional theory (TDDFT), we observe spin-, valley-, and layer-polarized excited state populations upon excitation with circularly polarized pump pulses, followed by ultrafast (<100  fs) scattering of carriers towards the global minimum of the conduction band. TDDFT reveals the character of the conduction band, into which electrons are initially excited, to be two-dimensional and localized within individual layers, whereas at the minimum of the conduction band, states have a three-dimensional character, facilitating interlayer charge transfer. These results establish the optical control of coupled spin-, valley-, and layer-polarized states in centrosymmetric materials with locally broken symmetries and suggest the suitability of TMDC multilayer and heterostructure materials for valleytronic and spintronic device concepts.
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Bertoni
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: C W
authors.initials: CW
authors.lastname: Nicholson
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Waldecker
authors.affiliation: Nano-Bio Spectroscopy Group and ETSF, Universidad del Pais Vasco, CFM CSIC-UPV/EHU, 20018 San Sebastian, Spain.
authors.forename: H
authors.initials: H
authors.lastname: Hübener
authors.affiliation: University of Zurich, Department of Physics, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Monney
authors.affiliation: Nano-Bio Spectroscopy Group and ETSF, Universidad del Pais Vasco, CFM CSIC-UPV/EHU, 20018 San Sebastian, Spain.|Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Via Archirafi 36, I-90123 Palermo, Italy.
authors.forename: U
authors.initials: U
authors.lastname: De Giovannini
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Puppin
authors.affiliation: Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Hoesch
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom.
authors.forename: E
authors.initials: E
authors.lastname: Springate
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom.
authors.forename: R T
authors.initials: RT
authors.lastname: Chapman
authors.affiliation: Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, United Kingdom.
authors.forename: C
authors.initials: C
authors.lastname: Cacho
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Wolf
authors.affiliation: Nano-Bio Spectroscopy Group and ETSF, Universidad del Pais Vasco, CFM CSIC-UPV/EHU, 20018 San Sebastian, Spain.|Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Notkestraße 85, 22761 Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Rubio
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Ernstorfer