Generation and Evolution of Spin-, Valley-, and Layer-Polarized Excited Carriers in Inversion-Symmetric WSe2

2016/06/30 by Roman Bertoni, Christopher W. Nicholson, C. W. Nicholson +14 · 6 citations
Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Algorithm #Atomic physics #Computer science #Excited state #Geology #Inversion (geology) #MXene and MAX Phase Materials #Perovskite Materials and Applications #Physics #cond-mat.mes-hall #cond-mat.mtrl-sci

paper · pdf · doi:10.1103/physrevlett.117.277201

published as Phys. Rev. Lett. 117, 277201 (2016)

openalex created_date 2016/06/24 · openalex publication_date 2016/12/30 · arxiv created 2017/01/02 · arxiv updated 2017/01/04 · openalex updated_date 2026/08/06

Abstract

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.

Citations

• Self-interaction correction to density-functional approximations for many-electron systems
• Valley polarization in MoS2 monolayers by optical pumping
• Valley-selective circular dichroism of monolayer molybdenum disulphide

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