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RESEARCH PRODUCT
Generation and Evolution of Spin-, Valley-, and Layer-Polarized Excited Carriers in Inversion-Symmetric WSe2
R. BertoniC. NicholsonL. WaldeckerH. HübenerC. MonneyU. De GiovanniniM. PuppinM. HoeschE. SpringateR. ChapmanC. CachoM. WolfA. RubioR. Ernstorfersubject
Condensed Matter - Materials Sciencetr-ARPESCondensed Matter - Mesoscale and Nanoscale PhysicsTDDFT530 PhysicsMesoscale and Nanoscale Physics (cond-mat.mes-hall)Materials Science (cond-mat.mtrl-sci)FOS: Physical sciences10192 Physics Institute2D materialsSettore FIS/03 - Fisica Della Materia3100 General Physics and Astronomydescription
We report the spin-selective optical excitation of carriers in inversion-symmetric bulk samples of the transition metal dichalcogenide (TMDC) WSe2. 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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-12-30 |