Spin structure of K valleys in single-layer WS${}_2$ on Au(111)

Abstract

The spin structure of the valence and conduction bands at the $\overline{\text{K}}$ and $\overline{\text{K}}$' valleys of single-layer WS${}_2$ on Au(111) is determined by spin- and angle-resolved photoemission and inverse photoemission. The bands confining the direct band gap of 1.98 eV are out-of-plane spin polarized with spin-dependent energy splittings of 417 meV in the valence band and 16 meV in the conduction band. The sequence of the spin-split bands is the same in the valence and in the conduction bands and opposite at the $\overline{\text{K}}$ and the $\overline{\text{K}}$' high-symmetry points. The first observation explains "dark" excitons discussed in optical experiments, the latter points to coupled spin and valley physics in electron transport. The experimentally observed band dispersions are discussed along with band structure calculations for a freestanding single layer and for a single layer on Au(111).

arXiv comment6 pages, 4 figures. Supplement available. This supplement includes details of the fitting procedure to extract peak positions and a tutorial on obtaining individual spin spectra from raw (inverse) photoemission data

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Cited by in corpus (10)

• Angle-resolved photoemission spectroscopy
• Orbital-driven Rashba effect in a binary honeycomb monolayer AgTe
• Distinctive signatures of the spin- and momentum-forbidden dark exciton states in the photo-luminescences of strained WSe${}_2$ monolayers under thermalization
• Larger than 80% Valley Polarization of Free Carriers in Singly-Oriented Single Layer WS${}_2$ on Au(111)
• Nanoscale patterning of quasiparticle band alignment
• Accessing the spectral function of in operando devices by angle-resolved photoemission spectroscopy
• Charge transfer-induced Lifshitz transition and magnetic symmetry breaking in ultrathin CrSBr crystals
• Momentum-resolved linear dichroism in bilayer MoS${}_2$
• Electron-phonon coupling in single-layer MoS2
• Spin- and angle-resolved inverse photoemission setup with spin orientation independent from electron incidence angle