Optical investigation of monolayer and bulk tungsten diselenide (WSe${}_2$) in high magnetic fields

Abstract

Optical spectroscopy in high magnetic fields $B\le 65$ T is used to reveal the very different nature of carriers in monolayer and bulk transition metal dichalcogenides. In monolayer WSe${}_2$, the exciton emission shifts linearly with the magnetic field and exhibits a splitting which originates from the magnetic field induced valley splitting. The monolayer data can be described using a single particle picture with a Dirac-like Hamiltonian for massive Dirac fermions, with an additional term to phenomenologically include the valley splitting. In contrast, in bulk WSe${}_2$ where the inversion symmetry is restored, transmission measurements show a distinctly excitonic behavior with absorption to the 1s and 2s states. Magnetic field induces a spin splitting together with a small diamagnetic shift and cyclotron like behavior at high fields, which is best described within the hydrogen model.

just accepted in Nano Letters http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.5b00626 (equations corrected)

References in corpus (9)

• The Valley Hall Effect in MoS2 Transistors
• Tightly bound excitons in monolayer WSe2
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Optical signature of symmetry variations and spin-valley coupling in atomically thin tungsten dichalcogenides
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
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• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
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Cited by in corpus (8)

• Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
• Brightening of dark excitons in monolayers of semiconducting transition metal dichalcogenides
• Excitonic valley effects in monolayer WS${}_2$ under high magnetic fields
• Luminescent emission of excited Rydberg excitons from monolayer WSe2
• Magneto-optical transport properties of monolayer WSe2
• Probing valley filtering effect by Andreev reflection in zigzag graphene nanoribbon
• Revealing the nature of excitons in liquid exfoliated monolayer WS2
• Magneto photoluminescence measurements of tungsten disulphide monolayers