The spin structure of the valence and conduction bands at the K and K′ valleys of single-layer WS2 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 K and the 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).

Spin Structure of K Valleys in Single-Layer WS2 on Au(111)

Bignardi L.
Membro del Collaboration Group
;
HOFMANN, PHILIP
Membro del Collaboration Group
;
2018

Abstract

The spin structure of the valence and conduction bands at the K and K′ valleys of single-layer WS2 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 K and the 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).
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https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.136402
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2947363
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